CODEWITHSUNDEEP
javaregex
user1016403
user1016403

Reputation: 12631

Matching String regular expression in java?

I have below lines of java code.

            String string1 = "SAMPLE STRING";
            String string2 = "SAMPLE*";

            string2 = string2.replaceAll("\\*",".*").trim().toUpperCase();

            if(string1.matches(string2)){
                System.out.println("true");
            }else{
                System.out.println("false");
            }

Here i dont understand the regex meaning here. what does it mean? Can anyone please help me?

Thanks!

Upvotes: 0

Views: 146

Answers (2)

Abhishek
Abhishek

Reputation: 422

Regex "\*" simply means '', when applied on string2 = SAMPLE by replaceAll() the string2 became SAMPLE.* and this is again a regex used by Matcher for match().

"SAMPLE.*" simply accepts everything followed by "SAMPLE"

Hence, "SAMPLE STRING" matched "SAMPLE.*".

Similarly, "SAMPLE ", "SAMPLE 123SSS", "SAMPLE" etc. will match. But, " SAMPLE STRING" doesn't matches pattern "SAMPLE.*"

Upvotes: 0

m0skit0
m0skit0

Reputation: 25874

So your regex here is "\\*" which simply means character *. The replaceAll() here will replace all * characters in string2 with .*.

This is a common replace to have people use simplified regexes (like the ones used to match files, e.g. *.exe) and convert it to a PCRE regex, which is the regex used in Java.

Upvotes: 2

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