Do you feel bad because of the Python docs?

[MRAB]

On 2013-02-26 14:26, Chris Angelico wrote:
> On Wed, Feb 27, 2013 at 12:56 AM, Roy Smith <roy at panix.com> wrote:
>> When people ask PHP questions, the questions tend to be phrased as "what
>> do I type to get X", and the answers come back that way too.  The forums
>> are full of, "I had the same problem.  Somebody told me to do this.  I
>> don't really understand it, but it worked for me and maybe it'll work
>> for you too".
>
> A problem that's majorly exacerbated by the myriad ways of doing some
> things, with some of those ways deprecated and others theoretically
> plausible but hopelessly impractical.
>
> Here's an actual example that came up today at work. Suppose you have
> a user-provided string that's supposed to contain a URL, and you need
> to ensure that it doesn't have a trailing slash, so you can later add
> "/foo" or "/bar". (Or alternatively, ensure that it DOES have a
> trailing slash. Either works.) Start the timer, go find out how to do
> it. Assume you are broadly familiar with PHP, and know how to do the
> basics of string handling, and are competent at searching the web.
> Ready? Go!
>
> I'll wait for you to come back.
>
> ... Okay, some of you are back now. Just giving the stragglers time to
> finish losing their marbles...
>
> Alright. Here's what I found in a recreation of today's search.
> Google search: php last character of string
>
> http://php.net/manual/en/function.substr.php
> -- okay, so I can use substr, but not string indexing, to find out
> what the last character is
> -- "Returns the extracted part of string; or FALSE on failure, or an
> empty string." What kind of failures result in FALSE, and what kind in
> an empty string?
>
[snip]
The page http://php.net/manual/en/function.substr.php says:

     Description
         string substr ( string $string , int $start [, int $length ] )

OK. It then goes on to say:

     Parameters
         string
             The input string. Must be one character or longer.

What? The input string can't be an empty string?