Java string replaceAll method

Question

hi i want to use Java string replaceAll() method to replace "x3" with "multiplied by 3" in my text file. But there is a string occurence "xxx3" which i do not want to replace. how can I do it

Example :

        ACTUAL                                     DESIRED  
1)ENGAGE XX3 COLOGNE 165ML          ENGAGE XX3 COLOGNE 165ML
2)FDW MEN REFRESHING PULSE 125GMSX3   FDW MEN REFRESHING PULSE 125GMS multuiplied by 3

You can try a [negative lookbehind](http://www.regular-expressions.info/lookaround.html#lookbehind). — shmosel, Mar 07 '16 at 08:31
1)ENGAGE XX3 COLOGNE 165ML, here it should not replace 2)FDW MEN REFRESHING PULSE 125GMSX3, here it should replace — sujit, Mar 07 '16 at 08:37

Charly · Answer 1 · 2016-03-07T08:52:56.700

4

Try

StringName.replaceAll("(?<!x)x3", "multiplied by 3");

replaceAll method uses a regex as first argument, this pattern has two parts :

"x3" : each time the method finds "x3" in your string, there is a chance to match the pattern

"(?<!x)" is a negative lookbehind. That means : "If my current part of the string is precedeed by x, the pattern will not match, else it will"

e.g. : "(?<!example)x3" will match each "x3" in your string, except any "examplex3"

Hope it helped you

edited Mar 07 '16 at 08:52

answered Mar 07 '16 at 08:40

Charly

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looking at your example, i am not sure what prefix should be ignored. Do you want to ignore XX3 or XXX3, or both ? – Charly Mar 07 '16 at 08:45
it should ignore only "xx3" but can u explain ur code please – sujit Mar 07 '16 at 08:45

Java string replaceAll method

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