问题
How can I convert
ereg_replace(".*\.(.*)$","\\1",$imgfile);
to
preg_replace... ?
?
I'm having trouble with it?
回答1:
preg_replace("/.*\.(.*)$/", "\\1", "foo.jpg")
I don't know why PHP requires the / delimiters. The only reason Perl, JS, etc. have them is that they allow regex literals, which PHP doesn't.
回答2:
You should know 4 main things to port ereg patterns to preg:
Add delimiters(/):
'pattern' => '/pattern/'Escape delimiter if it is a part of the pattern:
'patt/ern' => '/patt\/ern/'
Achieve it programmatically in following way:$ereg_pattern = '<div>.+</div>';$preg_pattern = '/' .addcslashes($ereg_pattern, '/') . '/';eregi(case-insensitive matching):
'pattern' => '/pattern/i'So, if you are using eregi function for case insenstive matching, just add 'i' in the end of new pattern('/pattern/').ASCII values: In ereg, if you use number in the pattern, it is assumed that you are referring to the ASCII of a character. But in preg, number is not treated as ASCII value. So, if your pattern contain ASCII value in the ereg expression(for example: new line, tabs etc) then convert it to hexadecimal and prefix it with \x.
Example: 9(tab) becomes \x9 or alternatively use \t.
Hope this will help.
回答3:
delimiters, add any char to beginning and end of expression, in this case, and by tradition, the '/' character preg_replace('/.*\.(.*)$/',"\\1",$imgfile); The regex isn't very good, better to use strrpos and take substr().
Regex is slow, use this. $extension=substr($imgName,strrpos($imgName,'.'));
来源：https://stackoverflow.com/questions/2443895/ereg-replace-to-preg-replace