Everyone makes mistakes, even the good people at Yahoo!/Flickr. I’ve done this on OSNews – it’s broken for 20 seconds, but you still get emails and IMs from users. Many PHP functions take two arguments — a string an an array — and it’s tough to remember which comes first, because sometimes it’s the array, and sometimes it’s the string. So functions like array_keys() can be tricky without using php.net.

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