preg replace不会在php中替换

Question

i have this code to replace a pattern in a php date like this

$input = preg_replace('/\/\-\.\_\s/', '-', $date);

If i pass date in the form mm/dd/yyyy, preg_replace just gives me back the passed date

the expected output should be mm-dd-yyyy what could be wrong

Answer 1

The set of characters you intend to replace with - belong inside a [] character class. In there, the . does not require escaping.

$out = preg_replace('#[/._\s]#', '-', $date);

When you are dealing with / as one of your expected characters, it is recommended to use a different character such as # as the delimiter.

$date = '01/02/2013';
echo preg_replace('#[/._\s]#', '-', $date);
// 01-02-2013

$date = '01.02.2013';
echo preg_replace('#[/._\s]#', '-', $date);
// 01-02-2013

// Or mixed...
$date = '01 02/2013';
echo preg_replace('#[/._\s]#', '-', $date);
// 01-02-2013

In your attempt, not using a character class [] caused your expression to expect the characters /-._\s literally in succession.