matlab - check if variable exists in the workspace with cellfun -

matlab - check if variable exists in the workspace with cellfun -

consider next example:

dat1 = 1; dat2 = 2; variables = {'dat1','dat2'}; = cellfun(@(x)exist(x,'var'),variables); = 1:length(variables); a2(i) = exist(variables{i},'var'); end

why 'a' , 'a2' homecoming different values i.e. why using cellfun not state variables exist in workspace? missing?

ok, think understand what's going on here:

when phone call anonymous function, creates own workspace, normal function. however, new workspace not have access caller workspace.

thus

funh = @(x)exist(x,'var')

will ever homecoming 1 if supply 'x' input (funh('x')), since entire workspace consists of variable 'x'.

consequently,

funh = @(x)exist('x','var')

will homecoming 1, regardless of supply input.

there 2 possible ways around that:

(1) utilize evalin evaluate in caller's workspace

funh = @(x)evalin('caller',sprintf('exist(''%s'',''var'')',x))

(2) utilize output of whos, , check against list of existing variables

variables = {'dat1','dat2'}; allvariables = whos; a3 = ismember(variables,{allvariables.name})

matlab exists