CODEWITHSUNDEEP
javaregex
coutier eric
coutier eric

Reputation: 1019

Extract all characters after a sequence using regexp in java/android

Imagine these String:

String s = "firstpartie_FOO_lastpartieofthestring"

or

String s = "lllalal_FOOBBARR_lastpartieofthestringofthedead"

With regexp, i want to extract the string after the second "_".

I've tried this:

Pattern p = Pattern.compile("(?<=_[A-Z]*_)");
Matcher m = p.matcher("lllalal_FOOBBARR_lastpartieofthestringofthedead")

But how to finish the regexp to extract the string "lastpartieofthestringofthedead" ?

Upvotes: 0

Views: 175

Answers (3)

coutier eric
coutier eric

Reputation: 1019

I've found this way:

Pattern p = Pattern.compile("_[A-Z]*_(.*)");

I progress in regex study hi hi hi ;-)

Explained:

...after an underscore followed by any number (use of star) of uppercase chars =>    [A-Z]*, followed by another underscore =>    _[A-Z]*_

... , capture all characters =>   (.*)

Find example here: https://ideone.com/S5WJMr

Upvotes: 0

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626738

If you want to fix your approach, capture the rest of the string with a capturing group:

String s = "lllalal_FOOBBARR_lastpartieofthestringofthedead";
Pattern p = Pattern.compile("^[^_]*_[^_]*_(.*)", Pattern.DOTALL);
Matcher m = p.matcher(s);
if (m.find()) {
    System.out.println(m.group(1));
}
// => lastpartieofthestringofthedead

See the Java demo

Here, ^[^_]*_[^_]*_(.*) matches the start of string (^), 0+ chars other than _ ([^_]*), _, again 0+ chars other than _ and a _, and then captures the rest of the string into Group 1 (with (.*)).

Else, split into 3 parts with _:

String s = "lllalal_FOOBBARR_lastpartieofthestring_of_thedead";
String[] res = s.split("_", 3);
if (res.length > 2) {
    System.out.println(res[2]);
} 
// => lastpartieofthestring_of_thedead

See another demo

Upvotes: 3

Chris
Chris

Reputation: 2465

Try this, it looks for any amount of characters followed by a _ then another amount of characters followed by _ and captures everything else:

.*_.*_(.*)

And an example on Regex101:

https://regex101.com/r/sfVyL2/1

Upvotes: 1

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