Question

Take this example:

string1 = "aaxadfxasdf"

string2 = "asdfxadf"

string3 = "sadfas"

i need a pattern that matches x such that it returns a match for x only for string2.

Note: for the purpose of this question, i must use java regex. Also, i don’t have access to the code, so i can’t simply check the # of matches returned by the java regex object.

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Hey All,

Thanks for the responses, some of which do answer my question. My example wasn’t as specific as i needed it to be. So let me add this quirk to the mix:

what if i’m matching more than a single character?

string4 = "This is a sentence!"
string5 = "This is just another sentence with some repetition in it. This is a   sentence"
string6 = "this is"

In this case, i want to match “sentence” only if it appears in the string only once.

Also, though not represented in the example, i need to be able to search across lines.

Answer 1

^[a-wy-z]+x[a-wy-z]+$

I’m not sure if you are only expecting letters, or if symbols and numbers might be included before and after the x you want to match. If so, use [^x] instead of [a-wy-z], like so:

^[^x]+x[^x]+$

If you are also wanting to match x by itself, replace the + symbols with * like so:

^[a-wy-z]*x[a-wy-z]*$