CODEWITHSUNDEEP
javastring
Oti Na Nai
Oti Na Nai

Reputation: 1407

Java - String replace exact word

String x = "axe pickaxe";
x = x.replace("axe", "sword");
System.out.print(x);

By this code, I am trying to replace the exact word axe with sword. However, if I run this, it prints sword picksword while I would like to print sword pickaxe only, as pickaxe is a different word from axe although it contains it. How can I fix this? Thanks

Upvotes: 41

Views: 76159

Answers (6)

SubOptimal
SubOptimal

Reputation: 22973

Include the word boundary before and after the word you want to replace.

String x = "axe pickaxe axe";
x = x.replaceAll("\\baxe\\b", "sword");
System.out.print(x);

edit output

sword pickaxe sword

Upvotes: 19

Avinash Raj
Avinash Raj

Reputation: 174696

Some other answers suggest you to use \\b word boundaries to match an exact word. But \\bfoo\\b would match the substring foo in .foo.. If you don't want this type of behavior then you may consider using lookaround based regex.

System.out.println(string.replaceAll("(?<!\\S)axe(?!\\S)", "sword"));

Explanation:

  • (?<!\\S) Negative lookbehind which asserts that the match won't be preceded by a non-space character. i.e. the match must be preceded by start of the line boundary or a space.

  • (?!\\S) Negative lookahead which asserts that the match won't be followed by a non-space character, i.e. the match must be followed by end of the line boundary or space. We can't use (?<=^|\\s)axe(?=\\s|$) since Java doesn't support variable length lookbehind assertions.

DEMO

Upvotes: 14

Alvin Magalona
Alvin Magalona

Reputation: 771

If you only want to replace the first occurrence, there is a method replaceFirst in String object.

String x = "axe pickaxe";
x = x.replaceFirst("axe", "sword");
System.out.print(x); //returns sword pickaxe

Upvotes: 2

Veselin Davidov
Veselin Davidov

Reputation: 7071

System.out.println("axe pickaxe".replaceAll("\\baxe\\b", "sword"));

You need to use replaceAll instead of replace - because it can work with regular expressions. Then use the meta character \b which is for word boundary. In order to use it you need to escape the \ as double \ so the reges become \\baxe\\b

Upvotes: 3

Steve Chaloner
Steve Chaloner

Reputation: 8202

You can use \b to define the word boundary, so \baxe\b in this case.

x = x.replaceAll("\\baxe\\b");

Upvotes: 2

hiergiltdiestfu
hiergiltdiestfu

Reputation: 2357

Use a regex with word boundaries \b:

String s = "axe pickaxe";
System.out.println(s.replaceAll("\\baxe\\b", "sword"));

The backslash from the boundary symbol must be escaped, hence the double-backslashes.

Upvotes: 60

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