Regex : Using Regex in Java 8

Question

I want to manipulate a String, my String are :

 String string = "dfwx--05-dfpixc3"

I want my output to be like :

dfwx--05
dfpixc3

So the separator is - and not --

moreover, can I solve this problem using Matcher class Pattern class ?

Answer 1

You can use split with this regex \\b-\\b with Word Boundaries like so :

\\b represents an anchor like caret (it is similar to $ and ^ ) matching positions where one side is a word character (like \\w ) and the other side is not a word character (for instance it may be the beginning of the string or a space character).

String[] split = string.split("\\b-\\b");

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Because my String is variable There always a number after --

Another solution could be by using positive lookbehind, like so (?<=\\d)- :

String[] split = string.split("(?<=\\d)-");

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Outputs

[dfwx--05, dfpixc3]

Answer 2

You can make use of lookarounds:

(?<!-)-(?!-)

• (?<!-) - make sure the preceding char is not a dash
• - - make sure we are looking at a dash
• (?!-) - make sure the following char is not a dash

If I'm not mistaken, the code would be:

string.split("(?<!-)-(?!-)");

I don't know which online tester is best for Java but see https://regex101.com/r/LVXDdH/1 for a PCRE example.

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Thank you JGFMK for this Java specific test site:

https://repl.it/repls/ImpressionableBronzeMice