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How to know if a string is a valid matlab function ?

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Charly
Charly on 6 Mar 2014
Answered: Jos (10584) on 7 Mar 2014
Hi,
I'm looking for a function which can tell me if a string is a valid matlab function.
For exemple :
function_i_m_looking_for('sin'); % should return 1
function_i_m_looking_for('toto'); % should return 0
Thank you

Accepted Answer

Mehmet OZC
Mehmet OZC on 6 Mar 2014
You can simply run the function below, hope it helps.
function output = function_i_m_looking_for(x)
output = 1;
try
type(x)
catch
output = 0;
end
end
  1 Comment
per isakson
per isakson on 6 Mar 2014
To suppress the output to the screen, replace
type(x)
by
evalc( 'type( ''x'' )' );

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More Answers (3)

Walter Roberson
Walter Roberson on 6 Mar 2014
regexp(x, '^[A-Za-z]\w*$') && ismember(exist(x), [2 3 5 6])
The beginning bit filters out embedded operators and file extensions and directory specifiers that exist() would otherwise pay attention to. 2 would be .m file on your search path, 3 is mex file on search path, 5 is built-in MATLAB function, 6 is .p file on search path. You might also want to include 8 which is class name.
  3 Comments
per isakson
per isakson on 7 Mar 2014
I call it smart, however ...
>> str = '+';
>> regexp( str, '^[A-Za-z]\w*$' )
ans =
[]
>> regexp( str, '^[A-Za-z]\w*$' ) && true
Operands to the || and && operators must be convertible to logical scalar values.
>>
Why isn't there a regular expression function, which returns a logical value?
.
A modified one-liner
>> not(isempty(regexp( str, '^[A-Za-z]\w*$' ))) && true
ans =
0

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Charly
Charly on 6 Mar 2014
Thank you for your answers
  1 Comment
Jos (10584)
Jos (10584) on 6 Mar 2014
This will also work for non-functions, like text files etc ...

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