I need a regex that can return up to 10 characters in the middle of a file name.
filename: returns:
msl_0123456789_otherstuff.csv -> 0123456789
msl_test.xml -> test
anythingShort.w1 -> anythingSh
I can capture the beginning and end for removal with the following regex:
Regex.Replace(filename, "(^msl_)|([.][[:alnum:]]{1,3}$)", string.Empty); *
but I also need to have only 10 characters when I am done.
Explanation of the regex above:
(^msl_) - match lines that start with "msl_"
| - or
([.] - match a period
[[:alnum]]{1,3} - followed by 1-3 alphanumeric characters
$) - at the end of the line
Note [[:alnum:]] can't work in a .NET regex, because it does not support POSIX character classes. You may use \w (to match letters, digits, underscores) or [^\W_] (to match letters or digits).
You can use your regex and just keep the first 10 chars in the string:
new string(Regex.Replace(s, #"^msl_|\.\w{1,3}$","").Take(10).ToArray())
See the C# demo online:
var strings = new List<string> { "msl_0123456789_otherstuff.csv", "msl_test.xml", "anythingShort.w1" };
foreach (var s in strings)
{
Console.WriteLine("{0} => {1}", s, new string(Regex.Replace(s, #"^msl_|\.\w{1,3}$","").Take(10).ToArray()));
}
Output:
msl_0123456789_otherstuff.csv => 0123456789
msl_test.xml => test
anythingShort.w1 => anythingSh
Using replace with the alternation, removes either of the alternatives from the start and the end of the string, but it will also work when the extension is not present and does not take the number of chars into account in the middle.
If the file extension should be present you might use a capturing group and make msl_ optional at the beginning.
Then match 1-10 times a word character except the _ followed by matching optional word characters until the .
^(?:msl_)?([^\W_]{1,10})\w*\.[^\W_]{2,}$
.NET regex demo (Click on the table tab)
A bit broader match could be using \S instead of \w and match until the last dot:
^(?:msl_)?(\S{1,10})\S*\.[^\W_]{2,}$
See another regex demo | C# demo
string[] strings = {"msl_0123456789_otherstuff.csv", "msl_test.xml","anythingShort.w1", "123456testxxxxxxxx"};
string pattern = #"^(?:msl_)?(\S{1,10})\S*\.[^\W_]{2,}$";
foreach (String s in strings) {
Match match = Regex.Match(s, pattern);
if (match.Success)
{
Console.WriteLine(match.Groups[1]);
}
}
Output
0123456789
test
anythingSh
Related
I'm using Replace(#"[^a-zA-Z]+", "");
leave only letters, but I have a set of numbers or characters that I want to keep as well, ex: 122456 and 112466. But I'm having trouble leaving it only if it's this sequence:
ex input:
abc 1239 asm122456000
I want to:
abscasm122456
tried this: ([^a-zA-Z])+|(?!122456)
My answer doesn't applying Replace(), but achieves a similar result:
(?:[a-zA-Z]+|\d{6})
which captures the group (non-capturing group) with the alphabetic character(s) or a set of digits with 6 occurrences.
Regex 101 & Test Result
Join all the matching values into a single string.
using System.Linq;
Regex regex = new Regex("(?:[a-zA-Z]+|\\d{6})");
string input = "abc 1239 asm12245600";
string output = "";
var matches = regex.Matches(input);
if (matches.Count > 0)
output = String.Join("", matches.Select(x => x.Value));
Sample .NET Fiddle
Alternate way,
using .Split() and .All(),
string input = "abc 1239 asm122456000";
string output = string.Join("", input.Split().Where(x => !x.All(char.IsDigit)));
.NET Fiddle
It is very simple: you need to match and capture what you need to keep, and just match what you need to remove, and then utilize a backreference to the captured group value in the replacement pattern to put it back into the resulting string.
Here is the regex:
(122456|112466)|[^a-zA-Z]
See the regex demo. Details:
(122456|112466) - Capturing group with ID 1: either of the two alternatives
| - or
[^a-zA-Z] - a char other than an ASCII letter (use \P{L} if you need to match any char other than any Unicode letter).
Note the removed + quantifier as [^A-Za-z] also matches digits.
You need to use $1 in the replacement:
var result = Regex.Replace(text, #"(122456|112466)|[^a-zA-Z]", "$1");
so i would like to get words between underscores after second occurence of underscore
this is my string
ABC_BC_BE08_C1000004_0124
I've assembled this expresion
(?<=_)[^_]+
well it matches what i need but only skips the first word since there is no underscore before it. I would like it to skip ABC and BC and just get the last three strings, i've tried messing around but i am stuck and cant make it work. Thanks!
You can use a non-regex approach here with Split and Skip:
var text = "ABC_BC_BE08_C1000004_0124";
var result = text.Split('_').Skip(2);
foreach (var s in result)
Console.WriteLine(s);
Output:
BE08
C1000004
0124
See the C# demo.
With regex, you can use
var result = Regex.Matches(text, #"(?<=^(?:[^_]*_){2,})[^_]+").Cast<Match>().Select(x => x.Value);
See the regex demo and the C# demo. The regex matches
(?<=^(?:[^_]*_){2,}) - a positive lookbehind that matches a location that matches the following patterns immediately to the left of the current location:
^ - start of string
(?:[^_]*_){2,} - two or more ({2,}) sequences of any zero or more chars other than _ ([^_]*) and then a _ char
[^_]+ - one or more chars other than _
Usign .NET there is also a captures collection that you might use with a regex and a repeated catpure group.
^[^_]*_[^_]*(?:_([^_]+))+
The pattern matches:
^ Start of string
[^_]*_[^_]* Match any char except an _, match _ and again any char except _
(?: Non capture group
_([^_]+) Match _ and capture 1 or more times any char except _ in group 1
)+ Close the non capture group and repeat 1 or more times
.NET regex demo | C# demo
For example:
var pattern = #"^[^_]*_[^_]*(?:_([^_]+))+";
var str = "ABC_BC_BE08_C1000004_0124";
var strings = Regex.Match(str, pattern).Groups[1].Captures.Select(c => c.Value);
foreach (String s in strings)
{
Console.WriteLine(s);
}
Output
BE08
C1000004
0124
If you want to match only word characters in between the underscores, another option for a pattern could be using a negated character class [^\W_] excluding the underscore from the word characters in between:
^[^\W_]*_[^\W_]*(?:_([^\W_]+))+
I've got a random input string to validate and tokenize.
My aim is to check if my string has the following pattern
[a-zA-Z]{2}\d{2} (one or unlimited times) comma separated
So:
aa12,af43,ad46 -> is valid
,aa12,aa44 -> is NOT valid (initial comma)
aa12, -> is NOT valid ( trailing comma)
That's the first part, validation
Then, with the same regex I've got to create a group for each occurrence of the pattern (match collection)
So:
aa12,af34,tg53
is valid and must create the following groups
Group 1 -> aa12
Group 2 -> af34
Group 3 -> tg53
Is it possible to have it done with only one regex that validates and creates the groups?
I've written this
^([a-zA-Z]{2}\d{2})(?:(?:[,])([a-zA-Z]{2}\d{2})(?:[,])([a-zA-Z]{2}\d{2}))*(?:[,])([a-zA-Z]{2}\d{2})*|$
but even if it creates the groups more or less correctly, it lacks in the validation process, getting also strings that have a wrong pattern.
Any hints would be very very welcome
You can use
var text = "aa12,af43,ad46";
var pattern = #"^(?:([a-zA-Z]{2}\d{2})(?:,\b|$))+$";
var result = Regex.Matches(text, pattern)
.Cast<Match>()
.Select(x => x.Groups[1].Captures.Cast<Capture>().Select(m => m.Value))
.ToList();
foreach (var list in result)
Console.WriteLine(string.Join("; ", list));
# => aa12; af43; ad46
See the C# demo online and the regex demo.
Regex details
^ - start of string
(?:([a-zA-Z]{2}\d{2})(?:,\b|$))+ - one or more occurrences of
([a-zA-Z]{2}\d{2}) - Group 1: two ASCII letter and then two digits
(?:,\b|$) - either , followed with a word char or end of string
$ - end of string. You may use \z if you want to prevent matching trailing newlines, LF, chars.
Using the C# Regex.Split method, I would like to split strings that will always start with RepXYZ, Where the XYZ bit is a number that will always have either 3 or 4 characters.
Examples
"Rep1007$chkCheckBox"
"Rep127_Group_Text"
The results should be:
{"Rep1007","$chkCheckBox"}
{"Rep127","_Group_Text"}
So far I have tried (Rep)[\d]{3,4} and ((Rep)[\d]{3,4})+ but both of those are giving me unwanted results
Using Regex.Split often results in empty or unwanted items in the resulting array. Using (Rep)[\d]{3,4} in Regex.Split, will put Rep without the numbers into the resulting array. (Rep[\d]{3,4}) will put the Rep and the numbers into the result, but since the match is at the start, there will be an empty item in the array.
I suggest using Regex.Match here:
var match = Regex.Match(text, #"^(Rep\d+)(.*)$");
if (match.Success)
{
Console.WriteLine(match.Groups[1].Value);
Console.WriteLine(match.Groups[2].Value);
}
See the regex demo
Details:
^ - start of string
(Rep\d+) - capturing group 1: Rep and any one or more digits
(.*) - capturing group 2: any one or more chars other than a newline, as many as possible
$ - end of string.
A splitting approach is better implemented with a lookaround-based regex:
var results = Regex.Split(text, #"(?<=^Rep\d+)(?=[$_])");
See this regex demo.
(?<=^Rep\d+)(?=[$_]) splits a string at the location that is immediately preceded with Rep and one or more digits at the start of the string, and immediately followed with $ or _.
Try splitting on the regex pattern on either $ or _:
string input = "Rep127_Group_Text";
string[] parts = input.Split(new[] { '$', '_' }, 2);
foreach (string part in parts)
{
Console.WriteLine(part);
}
This prints:
Rep127
Group_Text
I want to be able to match the following examples and return array of matches
given text:
some word
another 50.00
some-more 10.10 text
another word
Matches should be (word, followed by space then decimal number (Optionally followed by another word):
another 50.00
some-more 10.10 text
I have the following so far:
string pat = #"\r\n[A-Za-z ]+\d+\.\d{1,2}([A-Za-z])?";
Regex r = new Regex(pat, RegexOptions.IgnoreCase);
Match m = r.Match(input);
but it only matches first item: another 50.00
You do not account for - with [A-Za-z ] and only match some text after a newline.
You can use the following regex:
[\p{L}-]+\p{Zs}*\d*\.?\d{1,2}(?:\p{Zs}*[\p{L}-]+)?
See the regex demo
The [\p{L}-]+ matches 1 or more letters and hyphens, \p{Zs}* matches 0 or more horizontal whitespace symbols, \d*\.?\d{1,2} matches a float number with 1 to 2 digits in the decimal part, and (?:\p{Zs}*[\p{L}-]+)? matches an optional word after the number.
Here is a C# snippet matching all occurrences based on Regex.Matches method:
var res = Regex.Matches(str, #"[\p{L}-]+\p{Zs}*\d*\.?\d{1,2}(?:\p{Zs}*[\p{L}-]+)?")
.Cast<Match>()
.Select(p => p.Value)
.ToList();
Just FYI: if you need to match whole words, you can also use word boundaries \b:
\b[\p{L}-]+\p{Zs}*\d*\.?\d{1,2}(?:\p{Zs}*[\p{L}-]+)?\b
And just another note: if you need to match diacritics, too, you may add \p{M} to the character class containing \p{L}:
[\p{L}\p{M}-]+\p{Zs}*\d*\.?\d{1,2}(?:\p{Zs}*[\p{L}\p{M}-]+)?\b