Case Insensitive variable for String replaceAll(,) method Java

Question

Can anyone help me with creating a regex for variables in java so that the string variable will be considered to be a case insensitive and replace each and every word like Access, access, etc with WINDOWS of any thing like that?

This is the code:

$html=html.replaceAll(label, "WINDOWS");

Notice that label is a string variable.

Why not simply add a case-insensitive String to the label String? `"(?i)"` — Hovercraft Full Of Eels, Jun 28 '12 at 00:35
Perhaps also note what replaceAll takes as a first argument... then post it as an answer? ;-) — , Jun 28 '12 at 00:36
@pst: I have to run and don't have time to test this. I'll leave it to you to post the tested answer. — Hovercraft Full Of Eels, Jun 28 '12 at 00:37
Possible duplicate of [How to replace case-insensitive literal substrings in Java](http://stackoverflow.com/questions/5054995/how-to-replace-case-insensitive-literal-substrings-in-java) — james.garriss, Jul 08 '16 at 17:51

Bohemian · Accepted Answer · 2018-08-03T20:23:26.967

Just add the "case insensitive" switch to the regex:

html.replaceAll("(?i)"+label, "WINDOWS");

Note: If the label could contain characters with special regex significance, eg if label was ".*", but you want the label treated as plain text (ie not a regex), add regex quotes around the label, either

html.replaceAll("(?i)\\Q" + label + "\\E", "WINDOWS");

or

html.replaceAll("(?i)" + Pattern.quote(label), "WINDOWS");

score 7 · Answer 2 · edited Jun 28 '12 at 02:16

7

String.replaceAll is equivalent to creating a matcher and calling its replaceAll method so you can do something like this to make it case insensitive:

html = Pattern.compile(label, Pattern.CASE_INSENSITIVE).matcher(html).replaceAll("WINDOWS");

See: String.replaceAll and Pattern.compile JavaDocs

edited Jun 28 '12 at 02:16

Bohemian

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answered Jun 28 '12 at 00:50

anttix

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Is there a significant impact on memory / performance when using case insensitive (in opposition to Java's default case sensitive replace() method) for large Strings? For example, a document containing predefined labels (variables) that can be replaced dynamically based on some app logic. – Andrei F Feb 07 '17 at 08:26

score 1 · Answer 3 · edited Jun 28 '12 at 01:13

1

Just use patterns and matcher. Here's the code

Pattern p = Pattern.compile("Your word", Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher("String containing words");
String result = m.replaceAll("Replacement word");

Using patterns is easy as they are not case insensitive.

For more information, see

Matchmaking with regular expressions

Java: Pattern and Matcher

edited Jun 28 '12 at 01:13

n00begon

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answered Jun 28 '12 at 00:48

Sri Harsha Chilakapati

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How come this is any different? str.replaceAll(reg, replacement) is exactly the same as Pattern.compile(reg).matcher(str).replaceAll(replacement) – anttix Jun 28 '12 at 00:51
Using matcher is case insensitive. See the article in javaworld – Sri Harsha Chilakapati Jun 28 '12 at 00:53
@SriHarshaChilakapati "It depends". Compare with anttix's answer. – Jun 28 '12 at 00:55
@pst Sorry, but I didn't see his. I had spent some time in writing the answer and in search of the links – Sri Harsha Chilakapati Jun 28 '12 at 01:04

score -1 · Answer 4 · edited Aug 30 '12 at 07:47

-1

I think but am not sure you want label to be something like [Aa][cC][cC][eE][sS][sS]

or alternatively do

html = Pattern.compile(lable, Pattern.CASE_INSENSITIVE)
        .matcher(html).replaceAll("WINDOWS");

edited Aug 30 '12 at 07:47

Shashank Kadne

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answered Jun 28 '12 at 00:59

blinkymomo

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Case Insensitive variable for String replaceAll(,) method Java

4 Answers4