read a file and covert it to two arrays

I have an ascii data file with the following content:

a=2

b=4

c=9

I need to read it and create two arrays: one containing the names of the variables and another containing the values of the variables, i.e.

vn=[a b c];

vv=[2 4 9];

I have no control on the input file, it's just given to me.

Any ideas?

Thanks

Robert

[Gani]

Can you upload a sample file ?

Answer 1

[Robert Jones]

here it is

[Image Analyst]

My answer below works with that just fine.

Answer 2

[Image Analyst]

Try this (untested)

% Open the file.
fileID = fopen(fullFileName, 'rt');
loopCounter = 1;
% Read the first line of the file.
textLine = fgetl(fileID);
while ischar(textLine)
    equalLocation = strfind(textLine, '=')
    ca{loopCounter, 1} = textLine(1:(equalLocation-1));
    ca{loopCounter, 2} = str2double(textLine((equalLocation+1):end))
    % Read the remaining lines of the file.
    fprintf('%s\n', textLine);
    % Read the next line.
    textLine = fgetl(fileID);
    loopCounter = loopCounter + 1;
end
% All done reading all lines, so close the file.
fclose(fileID);

ca is your cell array output.

[Robert Jones]

Thanks,

this way I get a cell array ca

I can get the names using vn=char(ca{:,1}); which gives the vector [a,b,c]

however vn=char(ca{:,2}); gives an empty vector.

What am I missing?

[Image Analyst]

I converted it to numbers with str2double. If you want the strings as strings instead of doubles, don't use str2double().

[Robert Jones]

I see,

this how I solved the problem, not sure if this is the most elegant, but vn=[a b c] and qq=[5,3,9]

Thank you

clc

clear all

fullFileName='data.txt';

% Open the file.

fileID = fopen(fullFileName, 'rt');

loopCounter = 1;

% Read the first line of the file.

textLine = fgetl(fileID);

while ischar(textLine)

equalLocation = strfind(textLine, '=');

ca{loopCounter, 1} = textLine(1:(equalLocation-1));

ca{loopCounter, 2} = textLine((equalLocation+1):end);

% Read the remaining lines of the file.

fprintf('%s\n', textLine);

% Read the next line.

textLine = fgetl(fileID);

loopCounter = loopCounter + 1;

end

% All done reading all lines, so close the file.

fclose(fileID);

vn=char(ca{:,1});

vv=char(ca{:,2});

for i=1:size(vv)

qq(i)=str2double(vv(i));

end

[Image Analyst]

You're right. Not elegant. No need at all for a second loop. If you want a numerical/double vector, qq, then just simply put qq into the loop instead of ca{loopCounter, 2}:

qq(loopCounter) = str2double(textLine((equalLocation+1):end))

And the reason I used a cell array instead of a character array is to be robust enough to handle possible cases where the letters before the equals sign are more than one, like a two letter variable instead of a one letter variable. If you know for a fact that you will ALWAYS have single letters then you can just put your vn into the loop along with the qq. Again, just a single for loop is needed, NOT two.

Answer 3

[Robert Jones]

Thank you