php preg_match_all construct pattern

Question

I'm trying construct preg_match_all to search for all the values found in a string that begins with [$_ and ends with _$], and store the found values in an array.

So, in the following example:

$str = "I have a [$_dog_$], a [$_cat_$], but not a ferret.";
preg_match_all($regex_pattern, $str, $normalPets);

$normalPets should contain [$_dog_$] and [$_cat_$].

What is the $regex_pattern for this?

Thanks

Thanks for the good example and explanation. But. What have you tried? — Martin Ender
– Martin Ender, Commented Oct 2, 2012 at 19:56
Please note when I posted this it removed the underscore before dog and after dog. It should be [$_dog_$] — user1344131
– user1344131, Commented Oct 2, 2012 at 19:59

Ska · Accepted Answer · 2012-10-02 20:05:48Z

2

Should be:

$regex_pattern = '/\[\$_.+_\$\]/U';

edited Oct 2, 2012 at 20:05

answered Oct 2, 2012 at 19:58

Ska

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5 Comments

Martin Ender Over a year ago

there is no need for the capturing group

Martin Ender Over a year ago

also you should include the underscores

Ska Over a year ago

added the underscores and removed capturing group

user1344131 Over a year ago

Thanks. You are a regex genius, although it's storing [$_dog_$] and [$_cat_$] twice. I can deal with that with an array function but is there something in the regex pattern that is causing the found values to be stored 2x?

Ska Over a year ago

The reason for this is the way how the result is stored in $normalPets. The first entry is for the whole match and all the following entries (in you case only one) for all sub patterns. Unless you use the PREG_SET_ORDER constant as the fourth parameter $normalPets[0] should contain your result.

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