m-files as function inputs in for loop
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Hi everyone!
I have a function.m that I run with an input.m like this:
function input
I'm trying to process a Monte Carlo Samples in this function. So I have a lot of m-files inputs: input_1.m, input_2.m, ..., input_n.m.
To process everything I set up this for loop:
for i = 1:n
filename = sprintf('%s_%d', 'input', i);
function filename
end
But the function doesn't recognize the string to run. The errors are:
Error using pdatvp_seq (line 49)
Data file not found: filename.
Error in run_test (line 4)
function filename
Someone knows how to help me to do the function recognize the string to run?
4 个评论
Matt J
2018-2-5
Bad idea creating a file called "function.m". "function" is a reserved MATLAB keyword.
Sarah Andrade
2018-2-6
What does progcoll look like? I'm not familiar with trying to just pass one .m file in after another like that. Usually you would pass in arguments in parentheses. Also, trying to simplify your question is good, but doing so by replacing real function names with 'function' is very confusing since it is a fundamental key word.
Sarah Andrade
2018-2-6
编辑：Sarah Andrade
2018-2-6
采纳的回答
One obvious problem is that you are using command syntax whereas you need to be using function syntax (note the parentheses!):
for k = 1:n
fname = sprintf('input_%d.m', k);
progcoll(fname)
end
Your original code did not work because with command syntax all trailing strings are interpreted literally, so the trailing filename is not interpreted as a variable containing a name, but instead simply as the string of characters 'filename'. I would recommend that you always use function syntax every time that you call a function. Read about the difference here:
It states "When a function input is a variable, you must use function syntax to pass the value to the function. Command syntax always passes inputs as literal text and cannot pass variable values"
更多回答（1 个）
Kai Domhardt
2018-2-6
As a general description, you have a function you want to call in an .m file:
.m
function out = target_fun(in)
...
end
main.m
fun_call = [fun_name, '(' fun_param ')'];
result = eval(fun_call);
For your use you can apply it like this:
for i = 1:n
filename = sprintf('%s_%d', 'input', i);
eval(filename)
end
3 个评论
Do NOT use eval to call a script/function! Using eval is massive overkill for the simple running of a script/function. Also, depending on what objects the compiler matches that string to (or what is contained in the string) there could be all sorts of unpredictable side effects and bugs: using eval is not a robust solution, and will increase the chance of bugs (and makes them harder to locate).
for k = 1:n
name = sprintf('name_%d', k);
run(name)
end
Note that run accepts an absolute/relative path, so those files can be anywhere on your computer/drives (and not just on the MATLAB path).
Functions: If you need to call multiple functions in a loop (optionally with any required input/output arguments) then use str2func:
for k = 1:n
fun = str2func(sprintf('name_%d', k));
[...] = fun(...);
end
PS: calling a script/function still does not answer the question. The problem lies elsewhere!
Sarah Andrade
2018-2-6
Greg
2018-2-15
I just want to re-iterate:
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