sort

Synopsis

Y = sort(X)
[Y,I] = sort(X)

sort(X), where X is a matrix of real values, sorts each column of X in ascending order. If X is a vector of real values, sort sorts the elements of X in ascending order. NaNs appear at the end of the sorted list, after the highest integers. For identical values in X, the location in the input vector or matrix determines location in the sorted list.

sort orders complex input according to magnitude. Again, NaNs are appear at the end of the sorted list. For identical values, the phase of the input value on the interval [-pi pi] determines the final location. (A value that occurs directly on the negative real axis has phase -pi.) If the phase of the values is equal, sort uses location in the input vector or matrix to determine location in the sorted list.

[Y,I] = sort(X), where X is a matrix, also returns an m-by-n index matrix I, with each column a permutation of 1:m, so that for j = 1:n, Y(:,j) = X(I(:,j),j). If X is a vector, I is an index vector, a permutation of 1:n, so that Y = X(I).

If X has repeated elements of equal value, indices are returned that preserve the original relative ordering.

When X is complex, the elements are sorted by abs(X).

Examples

Let X = magic(4)

X =
    16    2    3   13
     5   11   10    8
     9    7    6   12
     4   14   15    1

Then

[Y,I] = sort(X)

produces

Y =
     4    2    3    1
     5    7    6    8
     9   11   10   12
    16   14   15   13
           
 I =
     4    1    1    4
     2    3    3    2
     3    2    2    3
     1    4    4    1

sort

Purpose

Synopsis

Description

Examples

See Also