Question

What’s the regular expression to find \"

I think it’s this: '/\\"/' but I need to use it on a really large dataset so need to make sure this is correct.

I need to replace it with " so my code is : $data = preg_replace('/\\"/', '"', $data)

Is that correct?

Answer 1

For matching backslashes you need to ‘double-escape’ them, so you have four \ at the end:

$data = preg_replace('/\\\\"/', '"', $data);

Why you need 4 \: PHP parses a string \\" as \" and RegEx interprets this as " since in RegEx you don’t need to escape ". So it wont match \". \\\\" will be parsed as \\" which will be interpreted as \" by RegEx.