Given the string "ThisStringHasNoSpacesButItDoesHaveCapitals" what is the best way to add spaces before the capital letters. So the end string would be "This String Has No Spaces But It Does Have Capitals"
Here is my attempt with a RegEx
System.Text.RegularExpressions.Regex.Replace(value, "[A-Z]", " $0")
The regexes will work fine (I even voted up Martin Browns answer), but they are expensive (and personally I find any pattern longer than a couple of characters prohibitively obtuse)
This function
string AddSpacesToSentence(string text, bool preserveAcronyms)
{
if (string.IsNullOrWhiteSpace(text))
return string.Empty;
StringBuilder newText = new StringBuilder(text.Length * 2);
newText.Append(text[0]);
for (int i = 1; i < text.Length; i++)
{
if (char.IsUpper(text[i]))
if ((text[i - 1] != ' ' && !char.IsUpper(text[i - 1])) ||
(preserveAcronyms && char.IsUpper(text[i - 1]) &&
i < text.Length - 1 && !char.IsUpper(text[i + 1])))
newText.Append(' ');
newText.Append(text[i]);
}
return newText.ToString();
}
Will do it 100,000 times in 2,968,750 ticks, the regex will take 25,000,000 ticks (and thats with the regex compiled).
It's better, for a given value of better (i.e. faster) however it's more code to maintain. "Better" is often compromise of competing requirements.
Update
It's a good long while since I looked at this, and I just realised the timings haven't been updated since the code changed (it only changed a little).
On a string with 'Abbbbbbbbb' repeated 100 times (i.e. 1,000 bytes), a run of 100,000 conversions takes the hand coded function 4,517,177 ticks, and the Regex below takes 59,435,719 making the Hand coded function run in 7.6% of the time it takes the Regex.
Update 2
Will it take Acronyms into account? It will now!
The logic of the if statment is fairly obscure, as you can see expanding it to this ...
if (char.IsUpper(text[i]))
if (char.IsUpper(text[i - 1]))
if (preserveAcronyms && i < text.Length - 1 && !char.IsUpper(text[i + 1]))
newText.Append(' ');
else ;
else if (text[i - 1] != ' ')
newText.Append(' ');
... doesn't help at all!
Here's the original simple method that doesn't worry about Acronyms
string AddSpacesToSentence(string text)
{
if (string.IsNullOrWhiteSpace(text))
return "";
StringBuilder newText = new StringBuilder(text.Length * 2);
newText.Append(text[0]);
for (int i = 1; i < text.Length; i++)
{
if (char.IsUpper(text[i]) && text[i - 1] != ' ')
newText.Append(' ');
newText.Append(text[i]);
}
return newText.ToString();
}
Your solution has an issue in that it puts a space before the first letter T so you get
" This String..." instead of "This String..."
To get around this look for the lower case letter preceding it as well and then insert the space in the middle:
newValue = Regex.Replace(value, "([a-z])([A-Z])", "$1 $2");
Edit 1:
If you use #"(\p{Ll})(\p{Lu})" it will pick up accented characters as well.
Edit 2:
If your strings can contain acronyms you may want to use this:
newValue = Regex.Replace(value, #"((?<=\p{Ll})\p{Lu})|((?!\A)\p{Lu}(?>\p{Ll}))", " $0");
So "DriveIsSCSICompatible" becomes "Drive Is SCSI Compatible"
Didn't test performance, but here in one line with linq:
var val = "ThisIsAStringToTest";
val = string.Concat(val.Select(x => Char.IsUpper(x) ? " " + x : x.ToString())).TrimStart(' ');
I know this is an old one, but this is an extension I use when I need to do this:
public static class Extensions
{
public static string ToSentence( this string Input )
{
return new string(Input.SelectMany((c, i) => i > 0 && char.IsUpper(c) ? new[] { ' ', c } : new[] { c }).ToArray());
}
}
This will allow you to use MyCasedString.ToSentence()
I set out to make a simple extension method based on Binary Worrier's code which will handle acronyms properly, and is repeatable (won't mangle already spaced words). Here is my result.
public static string UnPascalCase(this string text)
{
if (string.IsNullOrWhiteSpace(text))
return "";
var newText = new StringBuilder(text.Length * 2);
newText.Append(text[0]);
for (int i = 1; i < text.Length; i++)
{
var currentUpper = char.IsUpper(text[i]);
var prevUpper = char.IsUpper(text[i - 1]);
var nextUpper = (text.Length > i + 1) ? char.IsUpper(text[i + 1]) || char.IsWhiteSpace(text[i + 1]): prevUpper;
var spaceExists = char.IsWhiteSpace(text[i - 1]);
if (currentUpper && !spaceExists && (!nextUpper || !prevUpper))
newText.Append(' ');
newText.Append(text[i]);
}
return newText.ToString();
}
Here are the unit test cases this function passes. I added most of tchrist's suggested cases to this list. The three of those it doesn't pass (two are just Roman numerals) are commented out:
Assert.AreEqual("For You And I", "ForYouAndI".UnPascalCase());
Assert.AreEqual("For You And The FBI", "ForYouAndTheFBI".UnPascalCase());
Assert.AreEqual("A Man A Plan A Canal Panama", "AManAPlanACanalPanama".UnPascalCase());
Assert.AreEqual("DNS Server", "DNSServer".UnPascalCase());
Assert.AreEqual("For You And I", "For You And I".UnPascalCase());
Assert.AreEqual("Mount Mᶜ Kinley National Park", "MountMᶜKinleyNationalPark".UnPascalCase());
Assert.AreEqual("El Álamo Tejano", "ElÁlamoTejano".UnPascalCase());
Assert.AreEqual("The Ævar Arnfjörð Bjarmason", "TheÆvarArnfjörðBjarmason".UnPascalCase());
Assert.AreEqual("Il Caffè Macchiato", "IlCaffèMacchiato".UnPascalCase());
//Assert.AreEqual("Mister Dženan Ljubović", "MisterDženanLjubović".UnPascalCase());
//Assert.AreEqual("Ole King Henry Ⅷ", "OleKingHenryⅧ".UnPascalCase());
//Assert.AreEqual("Carlos Ⅴº El Emperador", "CarlosⅤºElEmperador".UnPascalCase());
Assert.AreEqual("For You And The FBI", "For You And The FBI".UnPascalCase());
Assert.AreEqual("A Man A Plan A Canal Panama", "A Man A Plan A Canal Panama".UnPascalCase());
Assert.AreEqual("DNS Server", "DNS Server".UnPascalCase());
Assert.AreEqual("Mount Mᶜ Kinley National Park", "Mount Mᶜ Kinley National Park".UnPascalCase());
Welcome to Unicode
All these solutions are essentially wrong for modern text. You need to use something that understands case. Since Bob asked for other languages, I'll give a couple for Perl.
I provide four solutions, ranging from worst to best. Only the best one is always right. The others have problems. Here is a test run to show you what works and what doesn’t, and where. I’ve used underscores so that you can see where the spaces have been put, and I’ve marked as wrong anything that is, well, wrong.
Testing TheLoneRanger
Worst: The_Lone_Ranger
Ok: The_Lone_Ranger
Better: The_Lone_Ranger
Best: The_Lone_Ranger
Testing MountMᶜKinleyNationalPark
[WRONG] Worst: Mount_MᶜKinley_National_Park
[WRONG] Ok: Mount_MᶜKinley_National_Park
[WRONG] Better: Mount_MᶜKinley_National_Park
Best: Mount_Mᶜ_Kinley_National_Park
Testing ElÁlamoTejano
[WRONG] Worst: ElÁlamo_Tejano
Ok: El_Álamo_Tejano
Better: El_Álamo_Tejano
Best: El_Álamo_Tejano
Testing TheÆvarArnfjörðBjarmason
[WRONG] Worst: TheÆvar_ArnfjörðBjarmason
Ok: The_Ævar_Arnfjörð_Bjarmason
Better: The_Ævar_Arnfjörð_Bjarmason
Best: The_Ævar_Arnfjörð_Bjarmason
Testing IlCaffèMacchiato
[WRONG] Worst: Il_CaffèMacchiato
Ok: Il_Caffè_Macchiato
Better: Il_Caffè_Macchiato
Best: Il_Caffè_Macchiato
Testing MisterDženanLjubović
[WRONG] Worst: MisterDženanLjubović
[WRONG] Ok: MisterDženanLjubović
Better: Mister_Dženan_Ljubović
Best: Mister_Dženan_Ljubović
Testing OleKingHenryⅧ
[WRONG] Worst: Ole_King_HenryⅧ
[WRONG] Ok: Ole_King_HenryⅧ
[WRONG] Better: Ole_King_HenryⅧ
Best: Ole_King_Henry_Ⅷ
Testing CarlosⅤºElEmperador
[WRONG] Worst: CarlosⅤºEl_Emperador
[WRONG] Ok: CarlosⅤº_El_Emperador
[WRONG] Better: CarlosⅤº_El_Emperador
Best: Carlos_Ⅴº_El_Emperador
BTW, almost everyone here has selected the first way, the one marked "Worst". A few have selected the second way, marked "OK". But no one else before me has shown you how to do either the "Better" or the "Best" approach.
Here is the test program with its four methods:
#!/usr/bin/env perl
use utf8;
use strict;
use warnings;
# First I'll prove these are fine variable names:
my (
$TheLoneRanger ,
$MountMᶜKinleyNationalPark ,
$ElÁlamoTejano ,
$TheÆvarArnfjörðBjarmason ,
$IlCaffèMacchiato ,
$MisterDženanLjubović ,
$OleKingHenryⅧ ,
$CarlosⅤºElEmperador ,
);
# Now I'll load up some string with those values in them:
my #strings = qw{
TheLoneRanger
MountMᶜKinleyNationalPark
ElÁlamoTejano
TheÆvarArnfjörðBjarmason
IlCaffèMacchiato
MisterDženanLjubović
OleKingHenryⅧ
CarlosⅤºElEmperador
};
my($new, $best, $ok);
my $mask = " %10s %-8s %s\n";
for my $old (#strings) {
print "Testing $old\n";
($best = $old) =~ s/(?<=\p{Lowercase})(?=[\p{Uppercase}\p{Lt}])/_/g;
($new = $old) =~ s/(?<=[a-z])(?=[A-Z])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Worst:", $new;
($new = $old) =~ s/(?<=\p{Ll})(?=\p{Lu})/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Ok:", $new;
($new = $old) =~ s/(?<=\p{Ll})(?=[\p{Lu}\p{Lt}])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Better:", $new;
($new = $old) =~ s/(?<=\p{Lowercase})(?=[\p{Uppercase}\p{Lt}])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Best:", $new;
}
When you can score the same as the "Best" on this dataset, you’ll know you’ve done it correctly. Until then, you haven’t. No one else here has done better than "Ok", and most have done it "Worst". I look forward to seeing someone post the correct ℂ♯ code.
I notice that StackOverflow’s highlighting code is miserably stoopid again. They’re making all the same old lame as (most but not all) of the rest of the poor approaches mentioned here have made. Isn’t it long past time to put ASCII to rest? It doens’t make sense anymore, and pretending it’s all you have is simply wrong. It makes for bad code.
This Regex places a space character in front of every capital letter:
using System.Text.RegularExpressions;
const string myStringWithoutSpaces = "ThisIsAStringWithoutSpaces";
var myStringWithSpaces = Regex.Replace(myStringWithoutSpaces, "([A-Z])([a-z]*)", " $1$2");
Mind the space in front if "$1$2", this is what will get it done.
This is the outcome:
"This Is A String Without Spaces"
Binary Worrier, I have used your suggested code, and it is rather good, I have just one minor addition to it:
public static string AddSpacesToSentence(string text)
{
if (string.IsNullOrEmpty(text))
return "";
StringBuilder newText = new StringBuilder(text.Length * 2);
newText.Append(text[0]);
for (int i = 1; i < result.Length; i++)
{
if (char.IsUpper(result[i]) && !char.IsUpper(result[i - 1]))
{
newText.Append(' ');
}
else if (i < result.Length)
{
if (char.IsUpper(result[i]) && !char.IsUpper(result[i + 1]))
newText.Append(' ');
}
newText.Append(result[i]);
}
return newText.ToString();
}
I have added a condition !char.IsUpper(text[i - 1]). This fixed a bug that would cause something like 'AverageNOX' to be turned into 'Average N O X', which is obviously wrong, as it should read 'Average NOX'.
Sadly this still has the bug that if you have the text 'FromAStart', you would get 'From AStart' out.
Any thoughts on fixing this?
Inspired from #MartinBrown,
Two Lines of Simple Regex, which will resolve your name, including Acyronyms anywhere in the string.
public string ResolveName(string name)
{
var tmpDisplay = Regex.Replace(name, "([^A-Z ])([A-Z])", "$1 $2");
return Regex.Replace(tmpDisplay, "([A-Z]+)([A-Z][^A-Z$])", "$1 $2").Trim();
}
Here's mine:
private string SplitCamelCase(string s)
{
Regex upperCaseRegex = new Regex(#"[A-Z]{1}[a-z]*");
MatchCollection matches = upperCaseRegex.Matches(s);
List<string> words = new List<string>();
foreach (Match match in matches)
{
words.Add(match.Value);
}
return String.Join(" ", words.ToArray());
}
Make sure you aren't putting spaces at the beginning of the string, but you are putting them between consecutive capitals. Some of the answers here don't address one or both of those points. There are other ways than regex, but if you prefer to use that, try this:
Regex.Replace(value, #"\B[A-Z]", " $0")
The \B is a negated \b, so it represents a non-word-boundary. It means the pattern matches "Y" in XYzabc, but not in Yzabc or X Yzabc. As a little bonus, you can use this on a string with spaces in it and it won't double them.
What you have works perfectly. Just remember to reassign value to the return value of this function.
value = System.Text.RegularExpressions.Regex.Replace(value, "[A-Z]", " $0");
Here is how you could do it in SQL
create FUNCTION dbo.PascalCaseWithSpace(#pInput AS VARCHAR(MAX)) RETURNS VARCHAR(MAX)
BEGIN
declare #output varchar(8000)
set #output = ''
Declare #vInputLength INT
Declare #vIndex INT
Declare #vCount INT
Declare #PrevLetter varchar(50)
SET #PrevLetter = ''
SET #vCount = 0
SET #vIndex = 1
SET #vInputLength = LEN(#pInput)
WHILE #vIndex <= #vInputLength
BEGIN
IF ASCII(SUBSTRING(#pInput, #vIndex, 1)) = ASCII(Upper(SUBSTRING(#pInput, #vIndex, 1)))
begin
if(#PrevLetter != '' and ASCII(#PrevLetter) = ASCII(Lower(#PrevLetter)))
SET #output = #output + ' ' + SUBSTRING(#pInput, #vIndex, 1)
else
SET #output = #output + SUBSTRING(#pInput, #vIndex, 1)
end
else
begin
SET #output = #output + SUBSTRING(#pInput, #vIndex, 1)
end
set #PrevLetter = SUBSTRING(#pInput, #vIndex, 1)
SET #vIndex = #vIndex + 1
END
return #output
END
replaceAll("(?<=[^^\\p{Uppercase}])(?=[\\p{Uppercase}])"," ");
static string AddSpacesToColumnName(string columnCaption)
{
if (string.IsNullOrWhiteSpace(columnCaption))
return "";
StringBuilder newCaption = new StringBuilder(columnCaption.Length * 2);
newCaption.Append(columnCaption[0]);
int pos = 1;
for (pos = 1; pos < columnCaption.Length-1; pos++)
{
if (char.IsUpper(columnCaption[pos]) && !(char.IsUpper(columnCaption[pos - 1]) && char.IsUpper(columnCaption[pos + 1])))
newCaption.Append(' ');
newCaption.Append(columnCaption[pos]);
}
newCaption.Append(columnCaption[pos]);
return newCaption.ToString();
}
In Ruby, via Regexp:
"FooBarBaz".gsub(/(?!^)(?=[A-Z])/, ' ') # => "Foo Bar Baz"
I took Kevin Strikers excellent solution and converted to VB. Since i'm locked into .NET 3.5, i also had to write IsNullOrWhiteSpace. This passes all of his tests.
<Extension()>
Public Function IsNullOrWhiteSpace(value As String) As Boolean
If value Is Nothing Then
Return True
End If
For i As Integer = 0 To value.Length - 1
If Not Char.IsWhiteSpace(value(i)) Then
Return False
End If
Next
Return True
End Function
<Extension()>
Public Function UnPascalCase(text As String) As String
If text.IsNullOrWhiteSpace Then
Return String.Empty
End If
Dim newText = New StringBuilder()
newText.Append(text(0))
For i As Integer = 1 To text.Length - 1
Dim currentUpper = Char.IsUpper(text(i))
Dim prevUpper = Char.IsUpper(text(i - 1))
Dim nextUpper = If(text.Length > i + 1, Char.IsUpper(text(i + 1)) Or Char.IsWhiteSpace(text(i + 1)), prevUpper)
Dim spaceExists = Char.IsWhiteSpace(text(i - 1))
If (currentUpper And Not spaceExists And (Not nextUpper Or Not prevUpper)) Then
newText.Append(" ")
End If
newText.Append(text(i))
Next
Return newText.ToString()
End Function
The question is a bit old but nowadays there is a nice library on Nuget that does exactly this as well as many other conversions to human readable text.
Check out Humanizer on GitHub or Nuget.
Example
"PascalCaseInputStringIsTurnedIntoSentence".Humanize() => "Pascal case input string is turned into sentence"
"Underscored_input_string_is_turned_into_sentence".Humanize() => "Underscored input string is turned into sentence"
"Underscored_input_String_is_turned_INTO_sentence".Humanize() => "Underscored input String is turned INTO sentence"
// acronyms are left intact
"HTML".Humanize() => "HTML"
Seems like a good opportunity for Aggregate. This is designed to be readable, not necessarily especially fast.
someString
.Aggregate(
new StringBuilder(),
(str, ch) => {
if (char.IsUpper(ch) && str.Length > 0)
str.Append(" ");
str.Append(ch);
return str;
}
).ToString();
Found a lot of these answers to be rather obtuse but I haven't fully tested my solution, but it works for what I need, should handle acronyms, and is much more compact/readable than the others IMO:
private string CamelCaseToSpaces(string s)
{
if (string.IsNullOrEmpty(s)) return string.Empty;
StringBuilder stringBuilder = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
stringBuilder.Append(s[i]);
int nextChar = i + 1;
if (nextChar < s.Length && char.IsUpper(s[nextChar]) && !char.IsUpper(s[i]))
{
stringBuilder.Append(" ");
}
}
return stringBuilder.ToString();
}
In addition to Martin Brown's Answer, I had an issue with numbers as well. For Example: "Location2", or "Jan22" should be "Location 2", and "Jan 22" respectively.
Here is my Regular Expression for doing that, using Martin Brown's answer:
"((?<=\p{Ll})\p{Lu})|((?!\A)\p{Lu}(?>\p{Ll}))|((?<=[\p{Ll}\p{Lu}])\p{Nd})|((?<=\p{Nd})\p{Lu})"
Here are a couple great sites for figuring out what each part means as well:
Java Based Regular Expression Analyzer (but works for most .net regex's)
Action Script Based Analyzer
The above regex won't work on the action script site unless you replace all of the \p{Ll} with [a-z], the \p{Lu} with [A-Z], and \p{Nd} with [0-9].
Here's my solution, based on Binary Worriers suggestion and building in Richard Priddys' comments, but also taking into account that white space may exist in the provided string, so it won't add white space next to existing white space.
public string AddSpacesBeforeUpperCase(string nonSpacedString)
{
if (string.IsNullOrEmpty(nonSpacedString))
return string.Empty;
StringBuilder newText = new StringBuilder(nonSpacedString.Length * 2);
newText.Append(nonSpacedString[0]);
for (int i = 1; i < nonSpacedString.Length; i++)
{
char currentChar = nonSpacedString[i];
// If it is whitespace, we do not need to add another next to it
if(char.IsWhiteSpace(currentChar))
{
continue;
}
char previousChar = nonSpacedString[i - 1];
char nextChar = i < nonSpacedString.Length - 1 ? nonSpacedString[i + 1] : nonSpacedString[i];
if (char.IsUpper(currentChar) && !char.IsWhiteSpace(nextChar)
&& !(char.IsUpper(previousChar) && char.IsUpper(nextChar)))
{
newText.Append(' ');
}
else if (i < nonSpacedString.Length)
{
if (char.IsUpper(currentChar) && !char.IsWhiteSpace(nextChar) && !char.IsUpper(nextChar))
{
newText.Append(' ');
}
}
newText.Append(currentChar);
}
return newText.ToString();
}
For anyone who is looking for a C++ function answering this same question, you can use the following. This is modeled after the answer given by #Binary Worrier. This method just preserves Acronyms automatically.
using namespace std;
void AddSpacesToSentence(string& testString)
stringstream ss;
ss << testString.at(0);
for (auto it = testString.begin() + 1; it != testString.end(); ++it )
{
int index = it - testString.begin();
char c = (*it);
if (isupper(c))
{
char prev = testString.at(index - 1);
if (isupper(prev))
{
if (index < testString.length() - 1)
{
char next = testString.at(index + 1);
if (!isupper(next) && next != ' ')
{
ss << ' ';
}
}
}
else if (islower(prev))
{
ss << ' ';
}
}
ss << c;
}
cout << ss.str() << endl;
The tests strings I used for this function, and the results are:
"helloWorld" -> "hello World"
"HelloWorld" -> "Hello World"
"HelloABCWorld" -> "Hello ABC World"
"HelloWorldABC" -> "Hello World ABC"
"ABCHelloWorld" -> "ABC Hello World"
"ABC HELLO WORLD" -> "ABC HELLO WORLD"
"ABCHELLOWORLD" -> "ABCHELLOWORLD"
"A" -> "A"
A C# solution for an input string that consists only of ASCII characters. The regex incorporates negative lookbehind to ignore a capital (upper case) letter that appears at the beginning of the string. Uses Regex.Replace() to return the desired string.
Also see regex101.com demo.
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesButItDoesHaveCapitals";
// Use negative lookbehind to match all capital letters
// that do not appear at the beginning of the string.
var pattern = "(?<!^)([A-Z])";
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
Expected Output:
Input: [ThisStringHasNoSpacesButItDoesHaveCapitals]
Output: [This String Has No Spaces But It Does Have Capitals]
Update: Here's a variation that will also handle acronyms (sequences of upper-case letters).
Also see regex101.com demo and ideone.com demo.
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ";
// Use positive lookbehind to locate all upper-case letters
// that are preceded by a lower-case letter.
var patternPart1 = "(?<=[a-z])([A-Z])";
// Used positive lookbehind and lookahead to locate all
// upper-case letters that are preceded by an upper-case
// letter and followed by a lower-case letter.
var patternPart2 = "(?<=[A-Z])([A-Z])(?=[a-z])";
var pattern = patternPart1 + "|" + patternPart2;
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1$2");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
Expected Output:
Input: [ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ]
Output: [This String Has No Spaces ASCII But It Does Have Capitals LINQ]
Here is a more thorough solution that doesn't put spaces in front of words:
Note: I have used multiple Regexs (not concise but it will also handle acronyms and single letter words)
Dim s As String = "ThisStringHasNoSpacesButItDoesHaveCapitals"
s = System.Text.RegularExpressions.Regex.Replace(s, "([a-z])([A-Z](?=[A-Z])[a-z]*)", "$1 $2")
s = System.Text.RegularExpressions.Regex.Replace(s, "([A-Z])([A-Z][a-z])", "$1 $2")
s = System.Text.RegularExpressions.Regex.Replace(s, "([a-z])([A-Z][a-z])", "$1 $2")
s = System.Text.RegularExpressions.Regex.Replace(s, "([a-z])([A-Z][a-z])", "$1 $2") // repeat a second time
In:
"ThisStringHasNoSpacesButItDoesHaveCapitals"
"IAmNotAGoat"
"LOLThatsHilarious!"
"ThisIsASMSMessage"
Out:
"This String Has No Spaces But It Does Have Capitals"
"I Am Not A Goat"
"LOL Thats Hilarious!"
"This Is ASMS Message" // (Difficult to handle single letter words when they are next to acronyms.)
All the previous responses looked too over complicated.
I had string that had a mixture of capitals and _ so used, string.Replace() to make the _, " " and used the following to add a space at the capital letters.
for (int i = 0; i < result.Length; i++)
{
if (char.IsUpper(result[i]))
{
counter++;
if (i > 1) //stops from adding a space at if string starts with Capital
{
result = result.Insert(i, " ");
i++; //Required** otherwise stuck in infinite
//add space loop over a single capital letter.
}
}
}
Inspired by Binary Worrier answer I took a swing at this.
Here's the result:
/// <summary>
/// String Extension Method
/// Adds white space to strings based on Upper Case Letters
/// </summary>
/// <example>
/// strIn => "HateJPMorgan"
/// preserveAcronyms false => "Hate JP Morgan"
/// preserveAcronyms true => "Hate JPMorgan"
/// </example>
/// <param name="strIn">to evaluate</param>
/// <param name="preserveAcronyms" >determines saving acronyms (Optional => false) </param>
public static string AddSpaces(this string strIn, bool preserveAcronyms = false)
{
if (string.IsNullOrWhiteSpace(strIn))
return String.Empty;
var stringBuilder = new StringBuilder(strIn.Length * 2)
.Append(strIn[0]);
int i;
for (i = 1; i < strIn.Length - 1; i++)
{
var c = strIn[i];
if (Char.IsUpper(c) && (Char.IsLower(strIn[i - 1]) || (preserveAcronyms && Char.IsLower(strIn[i + 1]))))
stringBuilder.Append(' ');
stringBuilder.Append(c);
}
return stringBuilder.Append(strIn[i]).ToString();
}
Did test using stopwatch running 10000000 iterations and various string lengths and combinations.
On average 50% (maybe a bit more) faster than Binary Worrier answer.
private string GetProperName(string Header)
{
if (Header.ToCharArray().Where(c => Char.IsUpper(c)).Count() == 1)
{
return Header;
}
else
{
string ReturnHeader = Header[0].ToString();
for(int i=1; i<Header.Length;i++)
{
if (char.IsLower(Header[i-1]) && char.IsUpper(Header[i]))
{
ReturnHeader += " " + Header[i].ToString();
}
else
{
ReturnHeader += Header[i].ToString();
}
}
return ReturnHeader;
}
return Header;
}
This one includes acronyms and acronym plurals and is a bit faster than the accepted answer:
public string Sentencify(string value)
{
if (string.IsNullOrWhiteSpace(value))
return string.Empty;
string final = string.Empty;
for (int i = 0; i < value.Length; i++)
{
if (i != 0 && Char.IsUpper(value[i]))
{
if (!Char.IsUpper(value[i - 1]))
final += " ";
else if (i < (value.Length - 1))
{
if (!Char.IsUpper(value[i + 1]) && !((value.Length >= i && value[i + 1] == 's') ||
(value.Length >= i + 1 && value[i + 1] == 'e' && value[i + 2] == 's')))
final += " ";
}
}
final += value[i];
}
return final;
}
Passes these tests:
string test1 = "RegularOTs";
string test2 = "ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ";
string test3 = "ThisStringHasNoSpacesButItDoesHaveCapitals";
An implementation with fold, also known as Aggregate:
public static string SpaceCapitals(this string arg) =>
new string(arg.Aggregate(new List<Char>(),
(accum, x) =>
{
if (Char.IsUpper(x) &&
accum.Any() &&
// prevent double spacing
accum.Last() != ' ' &&
// prevent spacing acronyms (ASCII, SCSI)
!Char.IsUpper(accum.Last()))
{
accum.Add(' ');
}
accum.Add(x);
return accum;
}).ToArray());
In addition to the request, this implementation correctly saves leading, inner, trailing spaces and acronyms, for example,
" SpacedWord " => " Spaced Word ",
"Inner Space" => "Inner Space",
"SomeACRONYM" => "Some ACRONYM".
Related
I think I am too dumb to solve this problem...
I have some formulas which need to be "translated" from one syntax to another.
Let's say I have a formula that goes like that (it's a simple one, others have many "Ceilings" in it):
string formulaString = "If([Param1] = 0, 1, Ceiling([Param2] / 0.55) * [Param3])";
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
My attempt is to split the fomulaString at "Ceiling(" so I am able to iterate through the string array and insert my string at the correct index (counting every "(" and ")" to get the right index)
What I have so far:
//splits correct, but loses "CEILING("
string[] parts = formulaString.Split(new[] { "CEILING(" }, StringSplitOptions.None);
//splits almost correct, "CEILING(" is in another group
string[] parts = Regex.Split(formulaString, #"(CEILING\()");
//splits almost every letter
string[] parts = Regex.Split(formulaString, #"(?=[(CEILING\()])");
When everything is done, I concat the string so I have my complete formula again.
What do I have to set as Regex pattern to achieve this sample? (Or any other method that will help me)
part1 = "If([Param1] = 0, 1, ";
part2 = "Ceiling([Param2] / 0.55) * [Param3])";
//part3 = next "CEILING(" in a longer formula and so on...
As I mention in a comment, you almost got it: (?=Ceiling). This is incomplete for your use case unfortunately.
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
Depending on your regex engine (for example JS) this works:
string[] parts = Regex.Split(formulaString, #"(?<=Ceiling\([^)]*(?=\)))");
string modifiedFormula = String.join("; 1", parts);
The regex
(?<=Ceiling\([^)]*(?=\)))
(?<= ) Positive lookbehind
Ceiling\( Search for literal "Ceiling("
[^)] Match any char which is not ")" ..
* .. 0 or more times
(?=\)) Positive lookahead for ")", effectively making us stop before the ")"
This regex is a zero-assertion, therefore nothing is lost and it will cut your strings before the last ")" in every "Ceiling()".
This solution would break whenever you have nested "Ceiling()". Then your only solution would be writing your own parser for the same reasons why you can't parse markup with regex.
Regex.Replace(formulaString, #"(?<=Ceiling\()(.*?)(?=\))","$1; 1");
Note: This will not work for nested "Ceilings", but it does for Ceiling(), It will also not work fir Ceiling(AnotherFunc(x)). For that you need something like:
Regex.Replace(formulaString, #"(?<=Ceiling\()((.*\((?>[^()]+|(?1))*\))*|[^\)]*)(\))","$1; 1$3");
but I could not get that to work with .NET, only in JavaScript.
This is my solution:
private string ConvertCeiling(string formula)
{
int ceilingsCount = formula.CountOccurences("Ceiling(");
int startIndex = 0;
int bracketCounter;
for (int i = 0; i < ceilingsCount; i++)
{
startIndex = formula.IndexOf("Ceiling(", startIndex);
bracketCounter = 0;
for (int j = 0; j < formula.Length; j++)
{
if (j < startIndex) continue;
var c = formula[j];
if (c == '(')
{
bracketCounter++;
}
if (c == ')')
{
bracketCounter--;
if (bracketCounter == 0)
{
// found end
formula = formula.Insert(j, "; 1");
startIndex++;
break;
}
}
}
}
return formula;
}
And CountOccurence:
public static int CountOccurences(this string value, string parameter)
{
int counter = 0;
int startIndex = 0;
int indexOfCeiling;
do
{
indexOfCeiling = value.IndexOf(parameter, startIndex);
if (indexOfCeiling < 0)
{
break;
}
else
{
startIndex = indexOfCeiling + 1;
counter++;
}
} while (true);
return counter;
}
This is my code. How can I edit it to show every word which is at the odd position ONLY to be reversed?
for (int i = input.Length - 1; i >= 0; i--)
{
if (input[i] == ' ')
{
result = tmp + " " + result;
tmp = "";
}
else
tmp += input[i];
}
result = tmp + " " + result;
Console.WriteLine(result);
Example input:
"How are you today"
to output:
"How era you yadot"
Based on the position of a word ['How' -> 0] do not reverse; [are -> 1 odd index] Reverse
You can achieve it with the help of LINQ:
var input = "hello this is a test message";
var inputWords = input.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
var result = string.Join(" ",
inputWords.Select((w, i) =>
i % 2 == 0
? w
: new string(w.Reverse().ToArray())
));
Where w in the select is the word, and i is the index, starting at 0 for the first word. % is the modulus operator and gets the remainder. If i % 2 == 0 (i.e. i can be divided by 2 with no remainder), then the original is returned. If there is a remainder (odd) then the reversed word is returned. Finally, it's all wrapped up in a string.Join(" ", items); which turns it back into a normal string rather than an array of items.
Try it online
So far you have a string, like this:
string input = "I want to reverse all odd words (odd words only!).";
And you, naturally, want to perform the task. Now it's the main question what's an odd word?
If you mean word's position (I at position 0, want at 1 - should be reversed etc.)
then you can use regular expressions to match words and Linq to process them:
using System.Linq; // To reverse single word
using System.Text.RegularExpressions; // To match the words within the text
...
// Let's elaborate the test example: add
// 1. some punctuation - ()!. - to preserve it
// 2. different white spaces (spaces and tabulation - \t)
// to add difficulties for naive algorithms
// 3. double spaces (after "to") to mislead split based algorithms
string input = "I want to reverse all\todd words (odd words only!).";
int index = 0; // words' indexes start from zero
string result = Regex.Replace(
input,
"[A-Za-z']+", // word is letters and apostrophes
match => index++ % 2 == 0
? match.Value // Even words intact
: string.Concat(match.Value.Reverse())); // Odd words reversed
Console.WriteLine(result);
If you want to reverse the words with odd Length, i.e. I, all, odd then all you have to do is to change the condition to
match => match.Value % 2 == 0
Outcome:
I tnaw to esrever all ddo words (ddo words ylno!).
Please, notice, that the punctuation has been preserved (only words are reversed).
OP: Based on the position of a word ['How' -> 0] do not reverse; [are -> 1 odd index] Reverse
public static void Main()
{
string input = "How are you today Laken-C";
//As pointed out by #Dmitry Bychenko string input = "How are you today";
//(double space after How) leads to How are uoy today outcome
input = Regex.Replace(input, #"\s+", " ");
var inp = input.Split(' ').ToList();
for (int j = 0; j < inp.Count(); j++)
{
if(j % 2 == 1)
{
Console.Write(inp[j].Reverse().ToArray());
Console.Write(" ");
}
else
Console.Write(inp[j] + " ");
}
}
OUTPUT:
DEMO:
dotNetFiddle
try this is perfect working code..
static void Main(string[] args)
{
string orgstr = "my name is sagar";
string revstr = "";
foreach (var word in orgstr.Split(' '))
{
string temp = "";
foreach (var ch in word.ToCharArray())
{
temp = ch + temp;
}
revstr = revstr + temp + " ";
}
Console.Write(revstr);
Console.ReadKey();
}
Output: ym eman si ragas
I have a method which takes in a string, which contains various characters, but I'm only concerned about underscores '_' and dollar signs '$'. I want to split up the string into tokens by underscores as each piece b/w the underscores contains important information.
However, if a $ is contained in an area between underscores, then a token should be created from the last occurrence of an underscore to the end (ignoring any underscores in this last section).
Example
input: Hello_To_The$Great_World
expected tokens: Hello, To, The$Great_World
Question
I have a solution below, but I'm wondering is there a cleaner/more intuitive way of doing this than what I have below?
var aTokens = new List<string>();
var aPos = 0;
for (var aNum = 0; aNum < item.Length; aNum++)
{
if (aNum == item.Length - 1)
{
aTokens.Add(item.Substring(aPos, item.Length - aPos));
break;
}
if (item[aNum] == '$')
{
aTokens.Add(item.Substring(aPos, item.Length - aPos));
break;
}
if (item[aNum] == '_')
{
aTokens.Add(item.Substring(aPos, aNum - aPos));
aPos = aNum + 1;
}
}
You can split string by _ not having $ before them.
For that you can use the following regex:
(?<!\$.*)_
Sample code:
string input = "Hello_To_The$Great_World";
string[] output = Regex.Split(input, #"(?<!\$.*)_");
You also can do the task without regex and without loops, but with the help of 2 splits:
string input = "Hello_To_The$Great_World";
string[] temp = input.Split(new[] { '$' }, 2);
string[] output = temp[0].Split('_');
if (temp.Length > 1)
output[output.Length - 1] = output[output.Length - 1] + "$" + temp[1];
This method is not efficient or clean, but it gives you a general idea of how to do this:
Split your string into tokens
Find the index of the first string to contain $
Return a new array with the first n tokens and the final token is the remaining strings concatenated.
It's probably more useful to take advantage of IEnumerable or do things over a for loop instead of all this Array.Copy stuff... but you get the gist of it.
private string[] SomeMethod(string arg)
{
var strings = arg.Split(new[] { '_' });
var indexedValue = strings.Select((v, i) => new { Value = v, Index = i }).FirstOrDefault(x => x.Value.Contains("$"));
if (indexedValue != null)
{
var count = indexedValue.Index + 1;
string[] final = new string[count];
Array.Copy(strings, 0, final, 0, indexedValue.Index);
final[indexedValue.Index] = String.Join("_", strings, indexedValue.Index, strings.Length - indexedValue.Index);
return final;
}
return strings;
}
Here's my version (loops are so last year...)
const char dollar = '$';
const char underscore = '_';
var item = "Hello_To_The$Great_World";
var aTokens = new List<string>();
int dollarIndex = item.IndexOf(dollar);
if (dollarIndex >= 0)
{
int lastUnderscoreIndex = item.LastIndexOf(underscore, dollarIndex);
if (lastUnderscoreIndex >= 0)
{
aTokens.AddRange(item.Substring(0, lastUnderscoreIndex).Split(underscore));
aTokens.Add(item.Substring(lastUnderscoreIndex + 1));
}
else
{
aTokens.Add(item);
}
}
else
{
aTokens.AddRange(item.Split(underscore));
}
Edit:
I should have added, cleaner/more intuitive is very subjective, as you have found out by the variety of answers provided. From a maintainability point of view, it's much more important that the method you write to do the parsing is unit tested!
It's also an interesting exercise to test the performance of the various methods posted here - it quickly becomes apparent that your original version is much faster than using regular expressions! (Although in a real life situation, it's probably quite unlikely that the performance of this method will make any difference to your application!)
I need to parse a decimal integer that appears at the start of a string.
There may be trailing garbage following the decimal number. This needs to be ignored (even if it contains other numbers.)
e.g.
"1" => 1
" 42 " => 42
" 3 -.X.-" => 3
" 2 3 4 5" => 2
Is there a built-in method in the .NET framework to do this?
int.TryParse() is not suitable. It allows trailing spaces but not other trailing characters.
It would be quite easy to implement this but I would prefer to use the standard method if it exists.
You can use Linq to do this, no Regular Expressions needed:
public static int GetLeadingInt(string input)
{
return Int32.Parse(new string(input.Trim().TakeWhile(c => char.IsDigit(c) || c == '.').ToArray()));
}
This works for all your provided examples:
string[] tests = new string[] {
"1",
" 42 ",
" 3 -.X.-",
" 2 3 4 5"
};
foreach (string test in tests)
{
Console.WriteLine("Result: " + GetLeadingInt(test));
}
foreach (var m in Regex.Matches(" 3 - .x. 4", #"\d+"))
{
Console.WriteLine(m);
}
Updated per comments
Not sure why you don't like regular expressions, so I'll just post what I think is the shortest solution.
To get first int:
Match match = Regex.Match(" 3 - .x. - 4", #"\d+");
if (match.Success)
Console.WriteLine(int.Parse(match.Value));
There's no standard .NET method for doing this - although I wouldn't be surprised to find that VB had something in the Microsoft.VisualBasic assembly (which is shipped with .NET, so it's not an issue to use it even from C#).
Will the result always be non-negative (which would make things easier)?
To be honest, regular expressions are the easiest option here, but...
public static string RemoveCruftFromNumber(string text)
{
int end = 0;
// First move past leading spaces
while (end < text.Length && text[end] == ' ')
{
end++;
}
// Now move past digits
while (end < text.Length && char.IsDigit(text[end]))
{
end++;
}
return text.Substring(0, end);
}
Then you just need to call int.TryParse on the result of RemoveCruftFromNumber (don't forget that the integer may be too big to store in an int).
I like #Donut's approach.
I'd like to add though, that char.IsDigit and char.IsNumber also allow for some unicode characters which are digits in other languages and scripts (see here).
If you only want to check for the digits 0 to 9 you could use "0123456789".Contains(c).
Three example implementions:
To remove trailing non-digit characters:
var digits = new string(input.Trim().TakeWhile(c =>
("0123456789").Contains(c)
).ToArray());
To remove leading non-digit characters:
var digits = new string(input.Trim().SkipWhile(c =>
!("0123456789").Contains(c)
).ToArray());
To remove all non-digit characters:
var digits = new string(input.Trim().Where(c =>
("0123456789").Contains(c)
).ToArray());
And of course: int.Parse(digits) or int.TryParse(digits, out output)
This doesn't really answer your question (about a built-in C# method), but you could try chopping off characters at the end of the input string one by one until int.TryParse() accepts it as a valid number:
for (int p = input.Length; p > 0; p--)
{
int num;
if (int.TryParse(input.Substring(0, p), out num))
return num;
}
throw new Exception("Malformed integer: " + input);
Of course, this will be slow if input is very long.
ADDENDUM (March 2016)
This could be made faster by chopping off all non-digit/non-space characters on the right before attempting each parse:
for (int p = input.Length; p > 0; p--)
{
char ch;
do
{
ch = input[--p];
} while ((ch < '0' || ch > '9') && ch != ' ' && p > 0);
p++;
int num;
if (int.TryParse(input.Substring(0, p), out num))
return num;
}
throw new Exception("Malformed integer: " + input);
string s = " 3 -.X.-".Trim();
string collectedNumber = string.empty;
int i;
for (x = 0; x < s.length; x++)
{
if (int.TryParse(s[x], out i))
collectedNumber += s[x];
else
break; // not a number - that's it - get out.
}
if (int.TryParse(collectedNumber, out i))
Console.WriteLine(i);
else
Console.WriteLine("no number found");
This is how I would have done it in Java:
int parseLeadingInt(String input)
{
NumberFormat fmt = NumberFormat.getIntegerInstance();
fmt.setGroupingUsed(false);
return fmt.parse(input, new ParsePosition(0)).intValue();
}
I was hoping something similar would be possible in .NET.
This is the regex-based solution I am currently using:
int? parseLeadingInt(string input)
{
int result = 0;
Match match = Regex.Match(input, "^[ \t]*\\d+");
if (match.Success && int.TryParse(match.Value, out result))
{
return result;
}
return null;
}
Might as well add mine too.
string temp = " 3 .x£";
string numbersOnly = String.Empty;
int tempInt;
for (int i = 0; i < temp.Length; i++)
{
if (Int32.TryParse(Convert.ToString(temp[i]), out tempInt))
{
numbersOnly += temp[i];
}
}
Int32.TryParse(numbersOnly, out tempInt);
MessageBox.Show(tempInt.ToString());
The message box is just for testing purposes, just delete it once you verify the method is working.
I'm not sure why you would avoid Regex in this situation.
Here's a little hackery that you can adjust to your needs.
" 3 -.X.-".ToCharArray().FindInteger().ToList().ForEach(Console.WriteLine);
public static class CharArrayExtensions
{
public static IEnumerable<char> FindInteger(this IEnumerable<char> array)
{
foreach (var c in array)
{
if(char.IsNumber(c))
yield return c;
}
}
}
EDIT:
That's true about the incorrect result (and the maintenance dev :) ).
Here's a revision:
public static int FindFirstInteger(this IEnumerable<char> array)
{
bool foundInteger = false;
var ints = new List<char>();
foreach (var c in array)
{
if(char.IsNumber(c))
{
foundInteger = true;
ints.Add(c);
}
else
{
if(foundInteger)
{
break;
}
}
}
string s = string.Empty;
ints.ForEach(i => s += i.ToString());
return int.Parse(s);
}
private string GetInt(string s)
{
int i = 0;
s = s.Trim();
while (i<s.Length && char.IsDigit(s[i])) i++;
return s.Substring(0, i);
}
Similar to Donut's above but with a TryParse:
private static bool TryGetLeadingInt(string input, out int output)
{
var trimmedString = new string(input.Trim().TakeWhile(c => char.IsDigit(c) || c == '.').ToArray());
var canParse = int.TryParse( trimmedString, out output);
return canParse;
}
I have a string User name (sales) and I want to extract the text between the brackets, how would I do this?
I suspect sub-string but I can't work out how to read until the closing bracket, the length of text will vary.
If you wish to stay away from regular expressions, the simplest way I can think of is:
string input = "User name (sales)";
string output = input.Split('(', ')')[1];
A very simple way to do it is by using regular expressions:
Regex.Match("User name (sales)", #"\(([^)]*)\)").Groups[1].Value
As a response to the (very funny) comment, here's the same Regex with some explanation:
\( # Escaped parenthesis, means "starts with a '(' character"
( # Parentheses in a regex mean "put (capture) the stuff
# in between into the Groups array"
[^)] # Any character that is not a ')' character
* # Zero or more occurrences of the aforementioned "non ')' char"
) # Close the capturing group
\) # "Ends with a ')' character"
Assuming that you only have one pair of parenthesis.
string s = "User name (sales)";
int start = s.IndexOf("(") + 1;
int end = s.IndexOf(")", start);
string result = s.Substring(start, end - start);
Use this function:
public string GetSubstringByString(string a, string b, string c)
{
return c.Substring((c.IndexOf(a) + a.Length), (c.IndexOf(b) - c.IndexOf(a) - a.Length));
}
and here is the usage:
GetSubstringByString("(", ")", "User name (sales)")
and the output would be:
sales
Regular expressions might be the best tool here. If you are not famililar with them, I recommend you install Expresso - a great little regex tool.
Something like:
Regex regex = new Regex("\\((?<TextInsideBrackets>\\w+)\\)");
string incomingValue = "Username (sales)";
string insideBrackets = null;
Match match = regex.Match(incomingValue);
if(match.Success)
{
insideBrackets = match.Groups["TextInsideBrackets"].Value;
}
string input = "User name (sales)";
string output = input.Substring(input.IndexOf('(') + 1, input.IndexOf(')') - input.IndexOf('(') - 1);
A regex maybe? I think this would work...
\(([a-z]+?)\)
using System;
using System.Text.RegularExpressions;
private IEnumerable<string> GetSubStrings(string input, string start, string end)
{
Regex r = new Regex(Regex.Escape(start) +`"(.*?)"` + Regex.Escape(end));
MatchCollection matches = r.Matches(input);
foreach (Match match in matches)
yield return match.Groups[1].Value;
}
int start = input.IndexOf("(") + 1;
int length = input.IndexOf(")") - start;
output = input.Substring(start, length);
Use a Regular Expression:
string test = "(test)";
string word = Regex.Match(test, #"\((\w+)\)").Groups[1].Value;
Console.WriteLine(word);
input.Remove(input.IndexOf(')')).Substring(input.IndexOf('(') + 1);
The regex method is superior I think, but if you wanted to use the humble substring
string input= "my name is (Jayne C)";
int start = input.IndexOf("(");
int stop = input.IndexOf(")");
string output = input.Substring(start+1, stop - start - 1);
or
string input = "my name is (Jayne C)";
string output = input.Substring(input.IndexOf("(") +1, input.IndexOf(")")- input.IndexOf("(")- 1);
var input = "12(34)1(12)(14)234";
var output = "";
for (int i = 0; i < input.Length; i++)
{
if (input[i] == '(')
{
var start = i + 1;
var end = input.IndexOf(')', i + 1);
output += input.Substring(start, end - start) + ",";
}
}
if (output.Length > 0) // remove last comma
output = output.Remove(output.Length - 1);
output : "34,12,14"
Here is a general purpose readable function that avoids using regex:
// Returns the text between 'start' and 'end'.
string ExtractBetween(string text, string start, string end)
{
int iStart = text.IndexOf(start);
iStart = (iStart == -1) ? 0 : iStart + start.Length;
int iEnd = text.LastIndexOf(end);
if(iEnd == -1)
{
iEnd = text.Length;
}
int len = iEnd - iStart;
return text.Substring(iStart, len);
}
To call it in your particular example you can do:
string result = ExtractBetween("User name (sales)", "(", ")");
I'm finding that regular expressions are extremely useful but very difficult to write. So, I did some research and found this tool that makes writing them so easy.
Don't shy away from them because the syntax is difficult to figure out. They can be so powerful.
This code is faster than most solutions here (if not all), packed as String extension method, it does not support recursive nesting:
public static string GetNestedString(this string str, char start, char end)
{
int s = -1;
int i = -1;
while (++i < str.Length)
if (str[i] == start)
{
s = i;
break;
}
int e = -1;
while(++i < str.Length)
if (str[i] == end)
{
e = i;
break;
}
if (e > s)
return str.Substring(s + 1, e - s - 1);
return null;
}
This one is little longer and slower, but it handles recursive nesting more nicely:
public static string GetNestedString(this string str, char start, char end)
{
int s = -1;
int i = -1;
while (++i < str.Length)
if (str[i] == start)
{
s = i;
break;
}
int e = -1;
int depth = 0;
while (++i < str.Length)
if (str[i] == end)
{
e = i;
if (depth == 0)
break;
else
--depth;
}
else if (str[i] == start)
++depth;
if (e > s)
return str.Substring(s + 1, e - s - 1);
return null;
}
I've been using and abusing C#9 recently and I can't help throwing in Spans even in questionable scenarios... Just for the fun of it, here's a variation on the answers above:
var input = "User name (sales)";
var txtSpan = input.AsSpan();
var startPoint = txtSpan.IndexOf('(') + 1;
var length = txtSpan.LastIndexOf(')') - startPoint;
var output = txtSpan.Slice(startPoint, length);
For the OP's specific scenario, it produces the right output.
(Personally, I'd use RegEx, as posted by others. It's easier to get around the more tricky scenarios where the solution above falls apart).
A better version (as extension method) I made for my own project:
//Note: This only captures the first occurrence, but
//can be easily modified to scan across the text (I'd prefer Slicing a Span)
public static string ExtractFromBetweenChars(this string txt, char openChar, char closeChar)
{
ReadOnlySpan<char> span = txt.AsSpan();
int firstCharPos = span.IndexOf(openChar);
int lastCharPos = -1;
if (firstCharPos != -1)
{
for (int n = firstCharPos + 1; n < span.Length; n++)
{
if (span[n] == openChar) firstCharPos = n; //This allows the opening char position to change
if (span[n] == closeChar) lastCharPos = n;
if (lastCharPos > firstCharPos) break;
//This would correctly extract "sales" from this [contrived]
//example: "just (a (name (sales) )))(test"
}
return span.Slice(firstCharPos + 1, lastCharPos - firstCharPos - 1).ToString();
}
return "";
}
Much similar to #Gustavo Baiocchi Costa but offset is being calculated with another intermediate Substring.
int innerTextStart = input.IndexOf("(") + 1;
int innerTextLength = input.Substring(start).IndexOf(")");
string output = input.Substring(innerTextStart, innerTextLength);
I came across this while I was looking for a solution to a very similar implementation.
Here is a snippet from my actual code. Starts substring from the first char (index 0).
string separator = "\n"; //line terminator
string output;
string input= "HowAreYou?\nLets go there!";
output = input.Substring(0, input.IndexOf(separator));