Determine the type of input in a function??

is there a way to determine the type of input in a function?? For example,

Case 1: if input is a .mat file called 'input.mat' somefunction('input.mat') would recognize that the input is a .mat file

Case 2: if input is a mxn matrix variable called 'input' somefunction(input) would recognize the input as a matlab variable

Case 3: if input is an excel file .xlsx called 'input.xlsx' somefunction('input.xlsx') would recognize the input as an excel file.

Answer 1

[Matt Fig]

Well you can't really pass a .mat file or excel file to a MATLAB function. You can pass a string name of a file. So something like this would work:

function []=getinput(A)

if ischar(A)
   if strfind(A,'.mat')
       disp('A .mat file name')
   elseif strfind(A,'.xls')
       disp('A .xls file name')
   else
       disp('Unknown file type')
   end
else
    disp(['You passed a ',class(A)])
end

Now we can test it out from the command line:

>> getinput('myfile.xls')
A .xls file name
>> getinput('myfile.xlsx')
A .xls file name
>> getinput('myfile.mat')
A .mat file name
>> getinput('myfile.m')
Unknown file type
>> getinput(magic(3))
You passed a double
>> getinput(true(2))
You passed a logical

[S H]

Matt, thanks for the help. I was thinking something along the lines of the function "isa" but this will certainly do the trick! Thanks!

[Walter Roberson]

Watch out for 'input.mat.xls' which is a .xls file but the code above would detect as being .mat

[Daniel Shub]

You might want to use FILEPARTS instead of STRFIND.