问题
I use a regex pattern i preg_match php function. The pattern is let's say '/abc$/'. It matches both strings:
'abc'
and
'abc
'
The second one has the line break at its end. What would be the pattern that matches only this first string?
'abc'
回答1:
The reason why /abc$/ 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
来源：https://stackoverflow.com/questions/38190269/regex-pattern-that-matches-the-string-at-the-end-of-a-string-but-is-not-followed