java string replace all

Question

I have a two dimensional array that contains pairs of strings. If one string is found it should replace it with its pair.

The code:

 for (int i = 0; i < pairs.length; i++) {
        if (name.contains(pairs[i][0])) {
            name.replaceAll(pairs[i][0], abbr[i][1]);
        }
    }

It is not replacing the strings. What is the error?

Some sample input & expected output may help. As well as "review" it is case for replace() (or) replaceAll()? and last but not least, Strings are immutable. — kosa
– kosa, Commented Aug 29, 2012 at 20:51
Replace abbr[i][1] with pairs[i][1]...Also, use a Map<String,String> instead of bidimentional array... — CosmicGiant
– CosmicGiant, Commented Aug 29, 2012 at 20:52
I don't really get the question... Could you post the contents of the array BEFORE you run your code, and the desired contents of the array AFTER you run your code? — 11684
– 11684, Commented Aug 29, 2012 at 20:53

pb2q · Accepted Answer · 2012-08-29 20:50:46Z

4

You are neglecting to assign the result of replaceAll, and so the modification is lost.

Perhaps you want to keep the modified string as name:

for (int i = 0; i < pairs.length; i++) {
    if (name.contains(pairs[i][0])) {
        name = name.replaceAll(pairs[i][0], abbr[i][1]);
    }
}

Note that java String objects are immutable, so calling name.replaceAll doesn't modify name, it returns a new String with the modifications.

answered Aug 29, 2012 at 20:50

pb2q

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Comments

Shivan Dragon · Accepted Answer · 2012-08-29 20:51:17Z

2

String is immutable.

name.replaceAll(pairs[i][0], abbr[i][1]);

creates a new String (it doesn't modify the "name" String)

Try

name = name.replaceAll(pairs[i][0], abbr[i][1]);

answered Aug 29, 2012 at 20:51

Shivan Dragon

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Comments

SamuelDavis · Accepted Answer · 2012-08-29 23:26:03Z

0

A modified version of the string is being created, however it's return value is being lost.

name = name.replaceAll(pairs[i][0], abbr[i][1]);

should work.

edited Aug 29, 2012 at 23:26

answered Aug 29, 2012 at 20:53

SamuelDavis

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2 Comments

RNJ Over a year ago

I don't think the string is being modified. A new one is created with the modification and being passed back.

SamuelDavis Over a year ago

Thank you. I didn't realize I had written it that way! Edited my answer.

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