Series in PHP
Given a string of digits, output all the contiguous substrings of length `n` in that string.
1  exercism fetch php series

Series
Given a string of digits, output all the contiguous substrings of length n
in
that string.
For example, the string "49142" has the following 3digit series:
 491
 914
 142
And the following 4digit series:
 4914
 9142
And if you ask for a 6digit series from a 5digit string, you deserve whatever you get.
Note that these series are only required to occupy adjacent positions in the input; the digits need not be numerically consecutive.
Running the tests

Go to the root of your PHP exercise directory, which is
<EXERCISM_WORKSPACE>/php
. To find the Exercism workspace run1
% exercism debug  grep Workspace

Get PHPUnit if you don't have it already.

Execute the tests:
1
% ./phpunit.phar series/series_test.php
Source
A subset of the Problem 8 at Project Euler http://projecteuler.net/problem=8
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.