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phpregexstringline-breakspcre

regex pattern that matches the string at the end of a string but is not followed by line break

I use a regex pattern i preg_match php function. The pattern is let's say '/abc$/'. It matches both strings:

'abc'

and

'abc
'

The second one has the line break at its end. What would be the pattern that matches only this first string?

'abc'
Solution

  • The reason why /abc$/ matches both "abc\n" and "abc" is that $ matches the location at the end of the string, or (even without /m modifier) the position before the newline that is at the end of the string.

    You need the following regex:

    /abc\z/

    where \z is the unambiguous very end of the string, or

    /abc$/D

    where the /D modifier will make $ behave the same way as \z. See PHP.NET:

    The meaning of dollar can be changed so that it matches only at the very end of the string, by setting the PCRE_DOLLAR_ENDONLY option at compile or matching time.

    See the regex demo