Reading the required variables for a function

2013 11 5
3 个回答
更新时间：2013 11 5
2 次查看（30 天）

0 个投票

Is there a function that will read the number and names of variables needed to run a function. I'm working on a brute force solution now that just opens the function as a text file and searches for the function declaration then reads the strings between the parenthesis.

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Azzi Abdelmalek
Azzi Abdelmalek 2013-11-5
Do you want the number of variables or their names?
Adam
Adam 2013-11-5
Both, your answer is a viable option, but I don't see how it will read the variables if the function call is not the first line of the .m file.

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回答（3 个）

Azzi Abdelmalek
Azzi Abdelmalek 2013-11-5
编辑：Azzi Abdelmalek 2013-11-5

0 个投票

fid = fopen('file.m');
line=''
while isempty(line)
line=fgetl(fid)
end
fclose(fid);
v=regexp(line,'(?<=\().+(?=\))','match')
n=strfind(v{1},',') % number of variables
%If you want their names
w=regexp(v{1},',','split')

6 个评论
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Adam
Adam 2013-11-5
This is great unless the function call is not on the first line of the code.
Azzi Abdelmalek
Azzi Abdelmalek 2013-11-5
编辑：Azzi Abdelmalek 2013-11-5
the test while isempty(line) checks if the first lines are empty
Walter Roberson
Walter Roberson 2013-11-5
编辑：Walter Roberson 2013-11-5
Remember comment lines, and comments more generally.
Watch out for continuation lines.
Azzi Abdelmalek
Azzi Abdelmalek 2013-11-5
For comment we can add a test
if line(1)=='%'
line=''
end
Walter Roberson
Walter Roberson 2013-11-5
Comments can start anywhere on a line. Also, blanks are permitted on lines.
line = regexprep(line, {'%.*', '^s+'}, {'', ''});
Azzi Abdelmalek
Azzi Abdelmalek 2013-11-5
The first character of line is always different from ' '

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Adam
Adam 2013-11-5
编辑：Adam 2013-11-5

0 个投票

Thanks for the help Azzi. I never used the regexp function before. It works really well in this application.
function [nvars,vars] = req_variables(filename)
% % Open the file for reading only.
[fid,msg] = fopen(filename,'r');
if fid <= 0
disp('Was not able to open file');
disp(msg)
return;
end
% Read the file, line by line, until we find the function call
line = ' ';
while (~strcmp(line(1:8),'function'))
line = fgetl(fid);
end
% Read the variable names and number from the line
v=regexp(line,'(?<=\().+(?=\))','match');
nvars =strfind(v{1},','); % number of variables
vars=regexp(v{1},',','split');
%Close the file
fclose(fid);

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Adam
Adam
2013-11-5

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Azzi Abdelmalek
Azzi Abdelmalek
2013-11-5

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