Write both strings and numbers to a file?

Hello,

Is it possible using fprintf or another function to write both an array of strings and numerical values to a file? I would like to write the variables names as well as their numeric values.

Thank you, Kevin

Answer 1

[José-Luis]

Yes you can:

 s = 'I am a string';
 n = pi();
 fprintf(1,'%s %f',s,n); %Replace 1 with an actual fid

[Kevin Bachovchin]

Something's not working quite right. As an example, I have

syms a b c d e
alphabet = [a ; b; c ; d ; e]
numeric = [1 ; 2; 3; 4 ; 5]
fid = fopen('Test.txt','w+')
fprintf(fid,'%s %f',char(alphabet),numeric)
Test = fscanf(fid,'%s %f')

I need to be able to write and read "alphabet" and "numeric" because I need to exchange this data this way using TCP/IP communication.

[Image Analyst]

Don't have alphabet after the format string, put it inside :

fprintf(fid,'alphabet %f %f %f %f %f', numeric)

Either way you're typing it into that line of code, but where you put it makes all the difference.

[Kevin Bachovchin]

That works, but what would I do if I didn't know the number of elements in alphabet?

[Image Analyst]

That won't happen. You will know the name of your variable. If your variable name itself is variable, and stored in a variable, like your variable name is myVariableName, and sometimes that will contain the string 'alphabet' and other times it might contain 'starTrek' and other times it might be 'starWars', then treat it just as an ordinary string

fprintf(fid,'%s %f %f %f %f %f', myVariableName, numeric)

so you'll see starTrek, alphabet, or starWars depending on what happened to be inside the string. But you will and must know that the variable is called myVariableName, otherwise how can you possibly tell it what to write out?

Answer 2

[Star Strider]

If you are exchanging files with someone else who is using MATLAB, use a mat-file. They are easy to use, binary, so are smaller, and do not need formats to write or read. They also associate the variables with their values, and when the files are opened, the variables and values (string, symbolic, numeric, cell) are automatically loaded into the workspace of the function calling them.

See matfile and associated functions for details.

[Kevin Bachovchin]

mat-files are very helpful. Unfortunately in this case, I need to exchange variables and values between processors using TCP/IP communication.