Retrieving an array of values for an array of keys from a containers.map object

Question

Joanne 2011-9-28

My code uses a containers.map object smap. I currently have the following inside a loop with over 6 million iterations:

val(i) = smap(key(i))

I'd like to take it out of the loop to make it faster - I can make a cell array of the (string) keys called keyList, and I tried

val_arr = cellfun(@(x), smap(x), keyList, 'UniformOutput', 'false')

which works but is actually a few seconds slower than just calling it inside the loop. Can you suggest how I might do this faster?

Answer 1

Walter Roberson 2011-9-28

val_arr = cellfun(@(x), smap(x), keyList, 'UniformOutput', 'false')

is a syntax error, as it has no function body for the anonymous function.

If you remove the comma after @(x) then it becomes valid.

Joanne 2011-9-28

Sorry, that was a typing-from-memory error on my part (I don't have the code with me). The function _did_ work, but was slower. Pretend I wrote:

val_arr = cellfun(@(x) smap(x), keyList, 'UniformOutput', 'false')