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{{Sorting Algorithm}}
{{task}}
[[Category:Encyclopedia]]
 
'''Sorting''' is a way of arranging a group of things in a specified order. Normally, the order is a "natural order." Examples of natural orders are counting order or alphabetical order.
Sort an Array of Strings, from large to small and lexicographic for Strings of equal length
 
In computing, time and memory usage are of concern when sorting. Some algorithms are very fast, but use a lot of memory, or vice versa. Usually, speed has higher priority.
==[[Perl]]==
'''Interpeter:''' Perl
 
The speed of an algorithm is often determined by the number of compares and/or swaps required. This is denoted as its "order" and is shown in [[Big O]] notation.
===Numeric sort===
my @sorted = sort {$a<=>$b} (3, 6, 4, 5, 2, 7, 1);
 
For example, a [[Quicksort]] is usually noted for being of "order n log n" (where n is the size of the group). This shown in Big O notation as "O(''n log(n)'')."
===Alpha-Numeric sort===
my @sorted = sort ('this', 'that', 'and', 'the', 'other');
 
Sorting algorithms often have different orders depending on characteristics of the group being sorted.
Numeric sort or Alpha-Numeric sort if a numeric sort cannot be done
 
For example, the Quicksort will perform at O(''n^2'') when the group is already ordered. A sort which "swaps" elements within the group is called an "in-place sort." A sort which moves elements to another group, destroys, or simply ignores the original group is sometimes called an "out-of-place sort" or a "not-in-place sort." An example of an out-of-place sort is the [http://en.wikipedia.org/wiki/Counting_sort counting sort].
# note, this can be a oneliner
my @sorted = sort {
($a =~ /^\-?\d+\.?\d*$/ and $b =~ /^\-?\d+\.?\d*$/) ? $a <=> $b : $a cmp $b
} ('this', 'that', 'and', 'the', 'other', 3, 6, 4, 5, 2, 7, 1);
 
For complete implementations of various sorting algorithms, see [[:Category:Sorting Algorithms]].
==[[Python]]==
 
For examples of how to use sorting functionality provided by a language, see:
'''Interpreter:''' Python 2.5
* [[Sort an array of composite structures]]
 
* [[Sorting an Array of Integers]]
Python's lists have a method for in-place sorting; there's also a built-in <tt>sorted()</tt> method that
* [[Sorting Using a Custom Comparator]]
can sort any iterable.
 
# create a sample list
words = ['Long', 'words', 'are', 'more', 'interesting', 'than', 'short', 'ones']
# order it and keep the result on another variable
sorted_words = sorted(words, key = lambda word: (-len(word), word))
# sorted_words: ['interesting', 'short', 'words', 'Long', 'more', 'ones', 'than', 'are']
 
==[[Ruby]]==
#create a test array
ary=['Long','words','are','more','interesting','than','short','ones']
ary.sort_by {|a| [-a.size,a]}
# => ["interesting", "short", "words", "Long", "more", "ones", "than", "are"]
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