Question

How can I check in PHP if every text row starts with Foo?

I want to remove “Foo” at the beginng of rows, but only if every row starts with Foo.

$string = 'Foo A
Foo B
Foo C';

should return:
A
B
C

and

$string = 'Foo A
B
Foo C';

should return:
Foo A
B
Foo C

How could this be matched?

if ( preg_match("/^Foo/m", $string ) ) {
  $string = preg_replace('/^Foo /m', '', $string);
}

This matches only single rows, but as mentioned it should only apply if all rows start with “Foo “.

Test: http://codepad.viper-7.com/roZNEo

Answer 1

I modified the regex a bit to assert every line starts with "Foo".

if ( preg_match("/^((?:^|\n)Foo.*)+$/", $text ) ) {
    $text = preg_replace('/^Foo /m', '', $text);
}

http://codepad.viper-7.com/ail50t