user3716193 February 2016

How do I read comma separated values from a .txt file in MATLAB using textscan()?

I have a .txt file with rows consisting of three elements, a word and two numbers, separated by commas.

For example:

a,142,5
aa,3,0
abb,5,0
ability,3,0
about,2,0

I want to read the file and put the words in one variable, the first numbers in another, and the second numbers in another but I am having trouble with textscan.

This is what I have so far:

File = [LOCAL_DIR 'filetoread.txt'];
FID_File = fopen(File,'r');
[words,var1,var2] = textscan(File,'%s %f %f','Delimiter',',');
fclose(FID_File);

I can't seem to figure out how to use a delimiter with textscan.

Answers


rayryeng February 2016

horchler is indeed correct. You first need to open up the file with fopen which provides a file ID / pointer to the actual file. You'd then use this with textscan. Also, you really only need one output variable because each "column" will be placed as a separate column in a cell array once you use textscan. You also need to specify the delimiter to be the , character because that's what is being used to separate between columns. This is done by using the Delimiter option in textscan and you specify the , character as the delimiter character. You'd then close the file after you're done using fclose.

As such, you just do this:

File = [LOCAL_DIR 'filetoread.txt'];
f = fopen(File, 'r');
C = textscan(f, '%s%f%f', 'Delimiter', ',');
fclose(f);

Take note that the formatting string has no spaces because the delimiter flag will take care of that work. Don't add any spaces. C will contain a cell array of columns. Now if you want to split up the columns into separate variables, just access the right cells:

names = C{1};
num1 = C{2};
num2 = C{3};

These are what the variables look like now by putting the text you provided in your post to a file called filetoread.txt:

>> names

names = 

    'a'
    'aa'
    'abb'
    'ability'
    'about'

>> num1

num1 =

   142
     3
     5
     3
     2

>> num2

num2 =

     5
     0
     0
     0
     0

Take note that names is a cell array of names, so accessing the right name is done by simply doing n = names{ii};

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