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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
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<HEAD>
<TITLE>SORT Sort
</TITLE>
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<BODY>
<H2>SORT Sort
</H2>
<P>
Section: <A HREF=sec_array.html> Array Generation and Manipulations </A>
<H3>Usage</H3>
Sorts an n-dimensional array along the specified dimensional. The first
form sorts the array along the first non-singular dimension.
<PRE>
B = sort(A)
</PRE>
<P>
Alternately, the dimension along which to sort can be explicitly specified
<PRE>
B = sort(A,dim)
</PRE>
<P>
FreeMat does not support vector arguments for <code>dim</code> - if you need <code>A</code> to be
sorted along multiple dimensions (i.e., row first, then columns), make multiple
calls to <code>sort</code>. Also, the direction of the sort can be specified using the
<code>mode</code> argument
<PRE>
B = sort(A,dim,mode)
</PRE>
<P>
where <code>mode = 'ascend'</code> means to sort the data in ascending order (the default),
and <code>mode = 'descend'</code> means to sort the data into descending order.
When two outputs are requested from <code>sort</code>, the indexes are also returned.
Thus, for
<PRE>
[B,IX] = sort(A)
[B,IX] = sort(A,dim)
[B,IX] = sort(A,dim,mode)
</PRE>
<P>
an array <code>IX</code> of the same size as <code>A</code>, where <code>IX</code> records the indices of <code>A</code>
(along the sorting dimension) corresponding to the output array <code>B</code>.
Two additional issues worth noting. First, a cell array can be sorted if each
cell contains a <code>string</code>, in which case the strings are sorted by lexical order.
The second issue is that FreeMat uses the same method as MATLAB to sort complex
numbers. In particular, a complex number <code>a</code> is less than another complex
number <code>b</code> if <code>abs(a) < abs(b)</code>. If the magnitudes are the same then we
test the angle of <code>a</code>, i.e. <code>angle(a) < angle(b)</code>, where <code>angle(a)</code> is the
phase of <code>a</code> between <code>-pi,pi</code>.
<H3>Example</H3>
Here are some examples of sorting on numerical arrays.
<PRE>
--> A = int32(10*rand(4,3))
A =
8 9 3
7 2 1
3 0 3
3 10 5
--> [B,IX] = sort(A)
B =
3 0 1
3 2 3
7 9 3
8 10 5
IX =
3 3 2
4 2 1
2 1 3
1 4 4
--> [B,IX] = sort(A,2)
B =
3 8 9
1 2 7
0 3 3
3 5 10
IX =
3 1 2
3 2 1
2 1 3
1 3 2
--> [B,IX] = sort(A,1,'descend')
B =
8 10 5
7 9 3
3 2 3
3 0 1
IX =
1 4 4
2 1 1
3 2 3
4 3 2
</PRE>
<P>
Here we sort a cell array of strings.
<PRE>
--> a = {'hello','abba','goodbye','jockey','cake'}
a =
[hello] [abba] [goodbye] [jockey] [cake]
--> b = sort(a)
b =
[abba] [cake] [goodbye] [hello] [jockey]
</PRE>
<P>
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