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.
This question is related to
regex
^[^_]*_
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
no need to do a replacement. the regex will give you what u wanted directly:
"(?<=_)[^_]*\.jpg"
tested with grep:
echo "3.04_somename.jpg"|grep -oP "(?<=_)[^_]*\.jpg"
somename.jpg
Variant of Tim's one, good only on some implementations of Regex: ^.*?_
var subjectString = "3.04_somename.jpg";
var resultString = Regex.Replace(subjectString,
@"^ # Match start of string
.*? # Lazily match any character, trying to stop when the next condition becomes true
_ # Match the underscore", "", RegexOptions.IgnorePatternWhitespace);
In Javascript I would use /.*_/, meaning: match everything until _ (including)
Example:
console.log( 'hello_world'.replace(/.*_/,'') ) // 'world'
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);
}
...
I learned all my Regex from this website: http://www.zytrax.com/tech/web/regex.htm. Google on 'Regex tutorials' and you'll find loads of helful articles.
String regex = "[a-zA-Z]*\.jpg";
System.out.println ("somthing.jpg".matches (regex));
returns true.
Source: Stackoverflow.com