Read just [Brackets] string from a text file [duplicate] - c#

This question already has answers here:
C# Regex Split - everything inside square brackets
(2 answers)
Closed 4 years ago.
I have a text file named hello.txt with the following text:
[Hello] this is stack overflow and I Love [THIS] a lot. I use [Stack]
for help.
I want just [ ] (brackets string) in a listbox.
I tried:
using (StringReader reader = new StringReader(File Location))
{
string line;
while ((line = reader.ReadLine()) != null)
{
string input = line;
string output = input.Split('[', ']')[1];
MessageBox.Show(output);
}
}
But this doesn't work for me.


This is what you are looking for
string a = "Someone is [here]";
string b = Regex.Match(a, #"\[.*?\]").Groups[0].Value;
Console.WriteLine(b);
//or if you need all occurences
foreach(Match match in Regex.Matches(a, #"\[.*?\]"))
{
Console.WriteLine(match.Groups[0].Value);
}


You can create a function for this which accept three parameter first input string, starting string and ending string and return list of value between those two string
private static IEnumerable<string> GetListOfString(string input, string start, string end)
{
var regex = new Regex(Regex.Escape(start) + "(.*?)" + Regex.Escape(end));
var matches = regex.Matches(input);
return (from object match in matches select match.ToString()).ToList();
}


You can use a regular expression like:
var pattern = #"\[[^\]]*]";
while ((line = reader.ReadLine()) != null) {
var matches = Regex.Matches(line, pattern);
foreach (var m in matches) {
MessageBox.Show(m);
}
}
This pattern looks for anything between square brackets that is not a closing square bracket.
If you want the string between the brackets without the brackets themselves, you can trim the brackets from each match:
MessageBox.Show(m.Value.Substring(1, m.Value.Length - 2));
Or you can use this pattern:
var pattern = #"\[([^\]]*)]";
while ((line = reader.ReadLine()) != null) {
var matches = Regex.Matches(line, pattern);
foreach (Match m in matches) {
MessageBox.Show(m.Groups[1]);
}
}


Here is another way to do that using LINQ
string[] text = "[Hello] this is stack overflow and I Love [THIS] a lot. I use [Stack] for help.".Split(' ');
var wantedString = text.Where(s => s.StartsWith("[") && s.EndsWith("]"));
foreach(string word in wantedString)
{
Console.WriteLine(word);
}

Related

Getting a numbers from a string with chars glued

I need to recover each number in a glued string
For example, from these strings:
string test = "number1+3"
string test1 = "number 1+4"
I want to recover (1 and 3) and (1 and 4)
How can I do this?
CODE
string test= "number1+3";
List<int> res;
string[] digits= Regex.Split(test, #"\D+");
foreach (string value in digits)
{
int number;
if (int.TryParse(value, out number))
{
res.Add(number)
}
}

This regex should work
string pattern = #"\d+";
string test = "number1+3";
foreach (Match match in Regex.Matches(test, pattern))
Console.WriteLine("Found '{0}' at position {1}",
match.Value, match.Index);
Note that if you intend to use it multiple times, it's better, for performance reasons, to create a Regex instance than using this static method.
var res = new List<int>();
var regex = new Regex(#"\d+");
void addMatches(string text) {
foreach (Match match in regex.Matches(text))
{
int number = int.Parse(match.Value);
res.Add(number);
}
}
string test = "number1+3";
addMatches(test);
string test1 = "number 1+4";
addMatches(test1);
MSDN link.
Fiddle 1
Fiddle 2

This calls for a regular expression:
(\d+)\+(\d+)
Test it
Match m = Regex.Match(input, #"(\d+)\+(\d+)");
string first = m.Groups[1].Captures[0].Value;
string second = m.Groups[2].Captures[0].Value;

An alternative to regular expressions:
string test = "number 1+4";
int[] numbers = test.Replace("number", string.Empty, StringComparison.InvariantCultureIgnoreCase)
.Trim()
.Split("+", StringSplitOptions.RemoveEmptyEntries)
.Select(x => Convert.ToInt32(x))
.ToArray();

split string and store it in another variable in c# [duplicate]

This question already has answers here:
Split string using backslash
(3 answers)
Closed 5 years ago.
How to Read character after '\':
string PrName = "software\Plan Mobile";

First of all, do not forget #:
string PrName = #"software\Plan Mobile";
Next, if you want just the tail only (i.e. "Plan Mobile") then Substring will do:
// if no '\' found, the entire string will be return
string tail = PrName.Substring(PrName.IndexOf('\\') + 1);
If you want both (all parts), try Split:
// parts[0] == "software"
// parts[1] == "Plan Mobile"
string[] parts = PrName.Split('\\');

Try this:
char charToFind = '\';
string PrName = "software\Plan Mobile";
int indexOfChar = PrName.IndexOf(charToFind);
if (indexOfChar >= 0)
{
string result = PrName.Substring(indexOfChar + 1);
}
Output: result = "Plan Mobile"

I think, you want to split string
string s = "software\Plan Mobile";
// Split string on '\'.
string[] words = s.Split('\');
foreach (string word in words)
{
Console.WriteLine(word);
}
Output:
software
Plan mobile

Get Expression in Named Capture

I am providing a textbox for one to enter a Regular Expression to match filenames. I plan to detect any named capture groups that they provide with the Regex method GetGroupNames().
I want to get the expression that they entered inside each named capture group.
As an example, they might enter a regular expression like this:
December (?<FileYear>\d{4}) Records\.xlsx
Is there a method or means to get the sub-expression \d{4} apart from manually parsing the regular expression string?

Here is an ugly brute force extension for parsing without using another Regex to detect the subexpression (or subpattern):
public static string GetSubExpression(this Regex pRegex, string pCaptureName)
{
string sRegex = pRegex.ToString();
string sGroupText = #"(?<" + pCaptureName + ">";
int iStartSearchAt = sRegex.IndexOf(sGroupText) + sGroupText.Length;
string sRemainder = sRegex.Substring(iStartSearchAt);
string sThis;
string sPrev = "";
int iOpenParenCount = 0;
int iEnd = 0;
for (int i = 0; i < sRemainder.Length; i++)
{
sThis = sRemainder.Substring(i, 1);
if (sThis == ")" && sPrev != #"\" && iOpenParenCount == 0)
{
iEnd = i;
break;
}
else if (sThis == ")" && sPrev != #"\")
{
iOpenParenCount--;
}
else if (sThis == "(" && sPrev != #"\")
{
iOpenParenCount++;
}
sPrev = sThis;
}
return sRemainder.Substring(0, iEnd);
}
The usage looks like this:
Regex reFromUser = new Regex(txtFromUser.Text);
string[] asGroupNames = reFromUser.GetGroupNames();
int iItsInt;
foreach (string sGroupName in asGroupNames)
{
if (!Int32.TryParse(sGroupName, out iItsInt)) //don't want numbered groups
{
string sSubExpression = reParts.GetSubExpression(sGroupName);
//Do what I need to do with the sub-expression
}
}
Now, if you would like to generate test or sample data, you can use the NuGet package called "Fare" in the following way after you get a sub-expression:
//Generate test data for it
Fare.Xeger X = new Fare.Xeger(sSubExpression);
string sSample = X.Generate();

This pattern (?<=\(\?<\w+\>)([^)]+) will give you all the named match capture expression with the name of the capture. It uses a negative look behind to make sure the text matched will have a (?<...> before it.
string data = #"December (?<FileYear>\d{4}) Records\.xlsx";
string pattern = #"(?<=\(\?<\w+\>)([^)]+)";
Regex.Matches(data, pattern)
.OfType<Match>()
.Select(mt => mt.Groups[0].Value)
returns one item of
\d{4}
While the data such as (?<FileMonth>[^\s]+)\s+(?<FileYear>\d{4}) Records\.xlsx would return two matches:
[^\s]+
\d{4}

Here is a solution using a regular expression to match the capturing groups in a regular expression. Idea is from this post Using RegEx to balance match parenthesis:
\(\?\<(?<MyGroupName>\w+)\>
(?<MyExpression>
((?<BR>\()|(?<-BR>\))|[^()]*)+
)
\)
or more concisely...
\(\?\<(?<MyGroupName>\w+)\>(?<MyExpression>((?<BR>\()|(?<-BR>\))|[^()]*)+)\)
and to use it might look like this:
string sGetCaptures = #"\(\?\<(?<MyGroupName>\w+)\>(?<MyExpression>((?<BR>\()|(?<-BR>\))|[^()]*)+)\)";
MatchCollection MC = Regex.Matches(txtFromUser.Text, sGetCaptures );
foreach (Match M in MC)
{
string sGroupName = M.Groups["MyGroupName"].Value;
string sSubExpression = M.Groups["MyExpression"].Value;
//Do what I need to do with the sub-expression
MessageBox.Show(sGroupName + ":" + sSubExpression);
}
And for the example in the original question, the message box would return FileYear:\d{4}

Retrieve String Containing Specific substring C#

I am having an output in string format like following :
"ABCDED 0000A1.txt PQRSNT 12345"
I want to retreieve substring(s) having .txt in above string. e.g. For above it should return 0000A1.txt.
Thanks

You can either split the string at whitespace boundaries like it's already been suggested or repeatedly match the same regex like this:
var input = "ABCDED 0000A1.txt PQRSNT 12345 THE.txt FOO";
var match = Regex.Match (input, #"\b([\w\d]+\.txt)\b");
while (match.Success) {
Console.WriteLine ("TEST: {0}", match.Value);
match = match.NextMatch ();
}

Split will work if it the spaces are the seperator. if you use oter seperators you can add as needed
string input = "ABCDED 0000A1.txt PQRSNT 12345";
string filename = input.Split(' ').FirstOrDefault(f => System.IO.Path.HasExtension(f));
filname = "0000A1.txt" and this will work for any extension

You may use c#, regex and pattern, match :)
Here is the code, plug it in try. Please comment.
string test = "afdkljfljalf dkfjd.txt lkjdfjdl";
string ffile = Regex.Match(test, #"\([a-z0-9])+.txt").Groups[1].Value;
Console.WriteLine(ffile);
Reference: regexp

I did something like this:
string subString = "";
char period = '.';
char[] chArString;
int iSubStrIndex = 0;
if (myString != null)
{
chArString = new char[myString.Length];
chArString = myString.ToCharArray();
for (int i = 0; i < myString.Length; i ++)
{
if (chArString[i] == period)
iSubStrIndex = i;
}
substring = myString.Substring(iSubStrIndex);
}
Hope that helps.

First split your string in array using
char[] whitespace = new char[] { ' ', '\t' };
string[] ssizes = myStr.Split(whitespace);
Then find .txt in array...
// Find first element starting with .txt.
//
string value1 = Array.Find(array1,
element => element.Contains(".txt", StringComparison.Ordinal));
Now your value1 will have the "0000A1.txt"
Happy coding.

Find substring ignoring specified characters

Do any of you know of an easy/clean way to find a substring within a string while ignoring some specified characters to find it. I think an example would explain things better:
string: "Hello, -this- is a string"
substring to find: "Hello this"
chars to ignore: "," and "-"
found the substring, result: "Hello, -this"
Using Regex is not a requirement for me, but I added the tag because it feels related.
Update:
To make the requirement clearer: I need the resulting substring with the ignored chars, not just an indication that the given substring exists.
Update 2:
Some of you are reading too much into the example, sorry, i'll give another scenario that should work:
string: "?A&3/3/C)412&"
substring to find: "A41"
chars to ignore: "&", "/", "3", "C", ")"
found the substring, result: "A&3/3/C)41"
And as a bonus (not required per se), it will be great if it's also not safe to assume that the substring to find will not have the ignored chars on it, e.g.: given the last example we should be able to do:
substring to find: "A3C412&"
chars to ignore: "&", "/", "3", "C", ")"
found the substring, result: "A&3/3/C)412&"
Sorry if I wasn't clear before, or still I'm not :).
Update 3:
Thanks to everyone who helped!, this is the implementation I'm working with for now:
http://www.pastebin.com/pYHbb43Z
An here are some tests:
http://www.pastebin.com/qh01GSx2
I'm using some custom extension methods I'm not including but I believe they should be self-explainatory (I will add them if you like)
I've taken a lot of your ideas for the implementation and the tests but I'm giving the answer to #PierrOz because he was one of the firsts, and pointed me in the right direction.
Feel free to keep giving suggestions as alternative solutions or comments on the current state of the impl. if you like.

in your example you would do:
string input = "Hello, -this-, is a string";
string ignore = "[-,]*";
Regex r = new Regex(string.Format("H{0}e{0}l{0}l{0}o{0} {0}t{0}h{0}i{0}s{0}", ignore));
Match m = r.Match(input);
return m.Success ? m.Value : string.Empty;
Dynamically you would build the part [-, ] with all the characters to ignore and you would insert this part between all the characters of your query.
Take care of '-' in the class []: put it at the beginning or at the end
So more generically, it would give something like:
public string Test(string query, string input, char[] ignorelist)
{
string ignorePattern = "[";
for (int i=0; i<ignoreList.Length; i++)
{
if (ignoreList[i] == '-')
{
ignorePattern.Insert(1, "-");
}
else
{
ignorePattern += ignoreList[i];
}
}
ignorePattern += "]*";
for (int i = 0; i < query.Length; i++)
{
pattern += query[0] + ignorepattern;
}
Regex r = new Regex(pattern);
Match m = r.Match(input);
return m.IsSuccess ? m.Value : string.Empty;
}

Here's a non-regex string extension option:
public static class StringExtensions
{
public static bool SubstringSearch(this string s, string value, char[] ignoreChars, out string result)
{
if (String.IsNullOrEmpty(value))
throw new ArgumentException("Search value cannot be null or empty.", "value");
bool found = false;
int matches = 0;
int startIndex = -1;
int length = 0;
for (int i = 0; i < s.Length && !found; i++)
{
if (startIndex == -1)
{
if (s[i] == value[0])
{
startIndex = i;
++matches;
++length;
}
}
else
{
if (s[i] == value[matches])
{
++matches;
++length;
}
else if (ignoreChars != null && ignoreChars.Contains(s[i]))
{
++length;
}
else
{
startIndex = -1;
matches = 0;
length = 0;
}
}
found = (matches == value.Length);
}
if (found)
{
result = s.Substring(startIndex, length);
}
else
{
result = null;
}
return found;
}
}

EDIT: here's an updated solution addressing the points in your recent update. The idea is the same except if you have one substring it will need to insert the ignore pattern between each character. If the substring contains spaces it will split on the spaces and insert the ignore pattern between those words. If you don't have a need for the latter functionality (which was more in line with your original question) then you can remove the Split and if checking that provides that pattern.
Note that this approach is not going to be the most efficient.
string input = #"foo ?A&3/3/C)412& bar A341C2";
string substring = "A41";
string[] ignoredChars = { "&", "/", "3", "C", ")" };
// builds up the ignored pattern and ensures a dash char is placed at the end to avoid unintended ranges
string ignoredPattern = String.Concat("[",
String.Join("", ignoredChars.Where(c => c != "-")
.Select(c => Regex.Escape(c)).ToArray()),
(ignoredChars.Contains("-") ? "-" : ""),
"]*?");
string[] substrings = substring.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
string pattern = "";
if (substrings.Length > 1)
{
pattern = String.Join(ignoredPattern, substrings);
}
else
{
pattern = String.Join(ignoredPattern, substring.Select(c => c.ToString()).ToArray());
}
foreach (Match match in Regex.Matches(input, pattern))
{
Console.WriteLine("Index: {0} -- Match: {1}", match.Index, match.Value);
}
Try this solution out:
string input = "Hello, -this- is a string";
string[] searchStrings = { "Hello", "this" };
string pattern = String.Join(#"\W+", searchStrings);
foreach (Match match in Regex.Matches(input, pattern))
{
Console.WriteLine(match.Value);
}
The \W+ will match any non-alphanumeric character. If you feel like specifying them yourself, you can replace it with a character class of the characters to ignore, such as [ ,.-]+ (always place the dash character at the start or end to avoid unintended range specifications). Also, if you need case to be ignored use RegexOptions.IgnoreCase:
Regex.Matches(input, pattern, RegexOptions.IgnoreCase)
If your substring is in the form of a complete string, such as "Hello this", you can easily get it into an array form for searchString in this way:
string[] searchString = substring.Split(new[] { ' ' },
StringSplitOptions.RemoveEmptyEntries);

This code will do what you want, although I suggest you modify it to fit your needs better:
string resultString = null;
try
{
resultString = Regex.Match(subjectString, "Hello[, -]*this", RegexOptions.IgnoreCase).Value;
}
catch (ArgumentException ex)
{
// Syntax error in the regular expression
}

You could do this with a single Regex but it would be quite tedious as after every character you would need to test for zero or more ignored characters. It is probably easier to strip all the ignored characters with Regex.Replace(subject, "[-,]", ""); then test if the substring is there.
Or the single Regex way
Regex.IsMatch(subject, "H[-,]*e[-,]*l[-,]*l[-,]*o[-,]* [-,]*t[-,]*h[-,]*i[-,]*s[-,]*")

Here's a non-regex way to do it using string parsing.
private string GetSubstring()
{
string searchString = "Hello, -this- is a string";
string searchStringWithoutUnwantedChars = searchString.Replace(",", "").Replace("-", "");
string desiredString = string.Empty;
if(searchStringWithoutUnwantedChars.Contains("Hello this"))
desiredString = searchString.Substring(searchString.IndexOf("Hello"), searchString.IndexOf("this") + 4);
return desiredString;
}

You could do something like this, since most all of these answer require rebuilding the string in some form.
string1 is your string you want to look through
//Create a List(Of string) that contains the ignored characters'
List<string> ignoredCharacters = new List<string>();
//Add all of the characters you wish to ignore in the method you choose
//Use a function here to get a return
public bool subStringExist(List<string> ignoredCharacters, string myString, string toMatch)
{
//Copy Your string to a temp
string tempString = myString;
bool match = false;
//Replace Everything that you don't want
foreach (string item in ignoredCharacters)
{
tempString = tempString.Replace(item, "");
}
//Check if your substring exist
if (tempString.Contains(toMatch))
{
match = true;
}
return match;
}

You could always use a combination of RegEx and string searching
public class RegExpression {
public static void Example(string input, string ignore, string find)
{
string output = string.Format("Input: {1}{0}Ignore: {2}{0}Find: {3}{0}{0}", Environment.NewLine, input, ignore, find);
if (SanitizeText(input, ignore).ToString().Contains(SanitizeText(find, ignore)))
Console.WriteLine(output + "was matched");
else
Console.WriteLine(output + "was NOT matched");
Console.WriteLine();
}
public static string SanitizeText(string input, string ignore)
{
Regex reg = new Regex("[^" + ignore + "]");
StringBuilder newInput = new StringBuilder();
foreach (Match m in reg.Matches(input))
{
newInput.Append(m.Value);
}
return newInput.ToString();
}
}
Usage would be like
RegExpression.Example("Hello, -this- is a string", "-,", "Hello this"); //Should match
RegExpression.Example("Hello, -this- is a string", "-,", "Hello this2"); //Should not match
RegExpression.Example("?A&3/3/C)412&", "&/3C\\)", "A41"); // Should match
RegExpression.Example("?A&3/3/C) 412&", "&/3C\\)", "A41"); // Should not match
RegExpression.Example("?A&3/3/C)412&", "&/3C\\)", "A3C412&"); // Should match
Output
Input: Hello, -this- is a string
Ignore: -,
Find: Hello this
was matched
Input: Hello, -this- is a string
Ignore: -,
Find: Hello this2
was NOT matched
Input: ?A&3/3/C)412&
Ignore: &/3C)
Find: A41
was matched
Input: ?A&3/3/C) 412&
Ignore: &/3C)
Find: A41
was NOT matched
Input: ?A&3/3/C)412&
Ignore: &/3C)
Find: A3C412&
was matched

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