[5.4] Add str_after helper function

[calebporzio]

I often come across cases where I need to retrieve everything after a piece of a string. Manually preg_match or strpos / substr is verbose IMO.

Here is the usage:

$title = str_after('Title: hello world', 'Title: ');

I've been using my own personal helper for this for some time now and have found it extremely handy, hoping you find the same!

Thanks for the endless amounts of hard work!

• Caleb

[devcircus]

Very useful. He rarely merges helpers that aren't used in the framework itself, but 'fingers-crossed'

[joshmanders]

I doubt the helper will get merged for the reason @devcircus said, but I wouldn't doubt the String::after function being merged.

[JosephSilber]

http://php.net/manual/en/function.strstr.php

[calebporzio]

@JosephSilber strstr returns a string including the search term. my str_after does not include the searched string.

[taylorotwell]

I can't decide what I think about returning empty string if the given string isn't present. To me it feels like I would want the whole string returned, since it most cases I would be using this function to trim a given string off the front of the other string. Thoughts?

[JosephSilber]

If it's a simple "trim this off this", why not use a preg_replace, with a leading ^

[taylorotwell]

I agree there are existing options if it's a leading trim, this would just be a more readable version of it maybe. Anyways, probably need @calebporzio to comment with his thoughts behind it.

[calebporzio]

I'm good with returning the entire string rather than empty. That makes more sense to me.

I thinkstr_after should not need the search string to be the start of the subject. A more fitting regex would be preg_replace('/^.*' . preg_quote($search) . '/')

I adjusted the implementation to return the full string on failure. I didn't go the regex route, let me know if that's a problem.

[sisve]

The docs for strpos

Returns FALSE if the needle was not found.

The docs for strstr ...

Returns the portion of string, or FALSE if needle is not found.

The docs for substr ...

Returns the extracted part of string; or FALSE on failure, or an empty string.

It kind of makes sense to keep the php tradition of returning false for these kind of string operations. Substr's empty string is a special case when pass $length = 0. If you you pass a $start which is after the length of the input you still get a false back.

If you want the original string if the needle is missing, use str_after($haystack, $needle) ?? $haystack (assuming PHP 7).

[vlakoff]

There is room for optimization in this code, and at least an unit test with empty search should be added, because strpos triggers a warning if needle is empty. Currently there is no error thanks to the above contains, but this one might get removed in the future.

[vlakoff]

strpos is single-byte while the rest of the code is utf8 aware.
Therefore you get wrong results with after('é foobarbaz', 'foo')

[vlakoff]

We grab up to the end, so the third parameter should be omitted.
(as more, here it exceeds the end the subject; it works but is erroneous)

[BrandonShar]

This seems unintuitive if there are multiple instances of the search string. I think I'd expect
str_after('Title: Title: hello world', 'Title: '); to return hello world, but it will return Title: hello world

[kingvish]

There can be third parameter offset like after($subject, $search, $offset) to skip number of character / occurrence.