regex to remove all text before a character

Question

Is there an easy way to remove all chars before a "_"? For example, change 3.04_somename.jpg to somename.jpg.

Any suggestions for where to learn to write regex would be great too. Most places I check are hard to learn from.

Answer 1

^[^_]*_ 

will match all text up to the first underscore. Replace that with the empty string.

For example, in C#:

resultString = Regex.Replace(subjectString,      @"^   # Match start of string     [^_]* # Match 0 or more characters except underscore     _     # Match the underscore", "", RegexOptions.IgnorePatternWhitespace); 

For learning regexes, take a look at http://www.regular-expressions.info

Answer 2

The regular expression:

^[^_]*_(.*)$ 

Then get the part between parenthesis. In perl:

my var = "3.04_somename.jpg"; $var =~ m/^[^_]*_(.*)$/; my fileName = $1; 

In Java:

String var = "3.04_somename.jpg"; String fileName = ""; Pattern pattern = Pattern.compile("^[^_]*_(.*)$"); Matcher matcher = pattern.matcher(var); if (matcher.matches()) {     fileName = matcher.group(1); } 

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