ind2vec

Convert indices to vectors

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Syntax

vec = ind2vec(ind)
vec = ind2vec(ind,N)

Description

vec = ind2vec(ind) takes a row vector of indices, ind, and returns a sparse matrix of vectors, vec, containing a 1 in the row of the index they represent, as indicated by ind.

ind2vec and vec2ind allow indices to be represented either by themselves, or as vectors containing a 1 in the row of the index they represent.

example

vec = ind2vec(ind,N) returns an N-by-M sparse matrix, where N can be equal to or greater than the maximum index.

example

Examples

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This example shows how to convert indices to vector representation using the ind2vec function.

Define four indices and then convert them to vector representation.

ind = [1 3 2 3];
vec = ind2vec(ind)
vec =
   (1,1)        1
   (3,2)        1
   (2,3)        1
   (3,4)        1

This example shows how to convert a vector to indices and back, using both the ind2vec and vec2ind functions.

Define a vector with all zeros in the last row and convert it to indices.

vec = [0 0 1 0; 1 0 0 0; 0 1 0 0]'
[ind,n] = vec2ind(vec)
vec =
     0     1     0
     0     0     1
     1     0     0
     0     0     0
ind =
     3     1     2

n =
     4

Convert the indices to vector, while preserving the number of rows.

vec2 = full(ind2vec(ind,n))
vec2 =
     0     1     0
     0     0     1
     1     0     0
     0     0     0

Input Arguments

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Indices, specified as a row vector.

Number of rows of the output matrix, specified as a scalar.

Output Arguments

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Vector representation of the indices, returned as an N-by-M sparse matrix.

Version History

Introduced before R2006a

See Also

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