Erlang Central

String Sort List

Revision as of 02:51, 4 September 2006 by Bfulgham (Talk | contribs)

Sorting a list of strings

Problem

You want to sort a list of strings.

Solution

Use the lists:sort operation to sort the lists. Note that by default sorting is case-sensitive. However, since you can use the lists:sort/2 variant of the function to supply your own sorting function this can be modified.

1> lists:sort(["foo", "bar", "baz", "qux"]).
["bar","baz","foo","qux"]
2> lists:sort(fun(A, B) -> A =< B end, ["foo", "bar", "baz", "qux"]).
["bar","baz","foo","qux"]
3> lists:sort(fun(A, B) -> A =< B end, ["foo", "bar", "baz", "qux"]).
["bar","baz","foo","qux"]
4> lists:sort(fun(A, B) -> A >= B end, ["foo", "bar", "baz", "qux"]).
["qux","foo","baz","bar"]

The sort operation uses the merge-sort algorithm, which takes time O(n log n) where n is the length of the list.