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Permutations

The Permutations constructor accepts two arguments: the number of items to take from a set and a list containing the items in the set.

For example, the following line creates a pseudo-list containing all the 3-permutations of the strings "a" to "e".

var p = new Permutations(3, characters("abcde"));

To see how many permutations are "contained" in p, we can check p.length. We can retrieve the individual permutations by index, e.g., p[0].

How are Permutations arranged?

In this library, Permutations are arrangements of items taken from a set for which:

• Order is important.
• Items are not replaced.

For example, consider the following set of trotters:

There are 60 3-permutations of trotters taken from this set. They are arranged by the algorithm (see Johnson-Steinhaus-Trotter) as follows:

(dot, dot, dot)