Simple apostrophe problem

[johnny44]

I want to replace all plain text apostrophe's ( ' ) in a certain string with the html variant ( ’ ). The apostrophes invariably come before letters like s, t and d. This code works fine:

 

$blah = str_replace( "'s" , "’s" , $blah );
$blah = str_replace( "'t" , "’t" , $blah );
$blah = str_replace( "'d" , "’d" , $blah );
...

 

but I trying to learn preg_replace. Nothing I have tried works. The closest I got is this:

 

$blah = preg_replace( "/'[a-z]/" , "’$0" , $blah );

 

but this just adds the html apostrophe without removing the plain one. Can anyone show me what would work?

[Orio]

$blah = preg_replace( "/'([a-z])/" , "’$1" , $blah );

 

Orio.

[johnny44]

Gosh, thanks Orio. Much appreciated !!

 

[effigy]

Or avoid the capture altogether:

 

$blah = preg_replace("/'(?=[a-z])/", '’', $blah );

[johnny44]

Avoid the capture. Good, good, good. Thanks Effigy.