I have a string: "Foo value 1.1.1".
I want to replace the 1.1.1 with something else, say ***?
I tried str.replaceAll("[0-9].[0-9].[0-9]", "***") and it works, but the word 1.1.1 can change and be "1.1" or "1.1.a" or "111", etc.
This word is always followed by the word "value" though. Thus I basically want to replace the word that comes after value, how can I do it using replaceAll.
You can use regex like (value\s)([\w\.?]+) to match and group it,then use $1 and $2 to replace it.
In your case,$1 represent for vaule\s and $2 represent [\w\.]+,we just need to reserve $1 and replace $2
String str1 = "Foo value 1.1.1".replaceAll("(value\\s)([\\w\\.?]+)", "$1AAA");
String str2 = "Foo value 1.1".replaceAll("(value\\s)([\\w\\.?]+)", "$1BBB");
String str3 = "Foo value Stackoverflow".replaceAll("(value\\s)([\\w\\.?]+)", "$1CCC");
System.out.println(str1);//output: Foo value AAA
System.out.println(str2);//output: Foo value BBB
System.out.println(str3);//output: Foo value CCC
Update,an more elegant way is to change regex to (?<=value\s)[\w\.?]+,output will be the same
String str1 = "Foo value 1.1.1".replaceAll("(?<=value\\s)[\\w\\.?]+", "AAA");
String str2 = "Foo value 1.1".replaceAll("(?<=value\\s)[\\w\\.?]+", "BBB");
String str3 = "Foo value Stackoverflow".replaceAll("(?<=value\\s)[\\w\\.?]+", "CCC");
System.out.println(str1);//output: Foo value AAA
System.out.println(str2);//output: Foo value BBB
System.out.println(str3);//output: Foo value CCC
Or, just to try something new :-p - you could try using a "positive lookbehind":
groovy:000> a = "hello there Moi"
groovy:000> p = java.util.regex.Pattern.compile("(?<=there\\s)\\w+")
groovy:000> m = p.matcher(a)
groovy:000> m.replaceAll("John")
===> hello there John
The regular expression (?<=there\\s)\\w+ will match any word, if it is preceded by "there " (with any whitespace character, not just space, after "there")
