subarray

Extracts a subarray from an array. Useful for function outputs.

Description

extracting a subarray from an array is simple:

a = 1:10;
a(4:8) %returns elements 4-8.

but sometimes, I have a function that returns an array, but I only want a subset of that array:

a = foo(x,y,z);
b = a(2,9:end);

Here 'a' is a temporary variable, polluting my workspace. Hence subarray:

b = subarray(foo(x,y,z),2,'9:end');

SUBARRAY should handle all the normal indexing cases (output of FIND, ranges, unspecified dimensions) just like the first example. The only exception is the 'end' keyword, where we have to pass in a string and EVAL it.

I tip my hat to Garret Euler of SUBMAT and SUBMAT_NOEVAL.

Acknowledgements

The author wishes to acknowledge the following in the creation of this submission:
submat, submat_noeval

• MATLAB release: MATLAB 7.8 (R2009a)

[Matt Fig]

You could also do this:

a = foo(x,y,z);
a = a(2,9:end);

Then there is no temporary variable polluting your workspace.

[Peter Mao]

I've noticed recently that using ":" in scripts works fine, but in a function, the call to subarray gets evaluated as the unknown variable "subarray"

Haven't got a solution for that yet.

[Oleg Komarov]

You don't have to eval it:

a = 1:10;
a(':')

The other case '9:end' could be handled w/o eval.