Reading text file with variable name

2 views (last 30 days)
Dear all
I wanted to read a text file with variable names in a loop. file names are 1.txt, 2.txt, 3.txt, and 4.txt. The files will be called during iteration repeatedly. I have an array that has the pattern of how the files should be called say: file_number=[1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4 ..]. I wonder if there is a way to call the files following this pattern.
Thanks

Accepted Answer

Voss
Voss on 17 Jun 2022
One way, using file_number in the file name:
file_number=[1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4];
for ii = 1:numel(file_number)
current_file_name = sprintf('%d.txt',file_number(ii))
% read the file current_file_name
end
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
Another way, which works for any set of file names:
file_number=[1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4];
file_names = {'a_file.txt' 'another_file.txt' 'yet_another_file.txt' 'you_guessed_it_another_file.txt'};
for ii = 1:numel(file_number)
current_file_name = sprintf('%s',file_names{file_number(ii)})
% read the file current_file_name
end
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
  2 Comments
Abdulaziz Abutunis
Abdulaziz Abutunis on 17 Jun 2022
Thank you very much
I found this works also
[num2str(file_number(i)),'.txt']
Voss
Voss on 17 Jun 2022
Edited: Voss on 17 Jun 2022
You're welcome! That's right, num2str also works!
As an alternative to all of these approaches, which create one file name at a time, it may be convenient to create all the file names at once, before the loop:
file_number=[1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4];
all_file_names = sprintfc('%d.txt',file_number)
all_file_names = 1×24 cell array
{'1.txt'} {'1.txt'} {'1.txt'} {'2.txt'} {'2.txt'} {'2.txt'} {'3.txt'} {'3.txt'} {'3.txt'} {'4.txt'} {'4.txt'} {'4.txt'} {'1.txt'} {'1.txt'} {'1.txt'} {'2.txt'} {'2.txt'} {'2.txt'} {'3.txt'} {'3.txt'} {'3.txt'} {'4.txt'} {'4.txt'} {'4.txt'}
for ii = 1:numel(file_number)
current_file_name = all_file_names{ii}
end
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '1.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '2.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '3.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
current_file_name = '4.txt'
file_number=[1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4];
file_names = {'a_file.txt' 'another_file.txt' 'yet_another_file.txt' 'you_guessed_it_another_file.txt'};
all_file_names = file_names(file_number)
all_file_names = 1×24 cell array
{'a_file.txt'} {'a_file.txt'} {'a_file.txt'} {'another_file.txt'} {'another_file.txt'} {'another_file.txt'} {'yet_another_file.txt'} {'yet_another_file.txt'} {'yet_another_file.txt'} {'you_guessed_it_another_file.txt'} {'you_guessed_it_another_file.txt'} {'you_guessed_it_another_file.txt'} {'a_file.txt'} {'a_file.txt'} {'a_file.txt'} {'another_file.txt'} {'another_file.txt'} {'another_file.txt'} {'yet_another_file.txt'} {'yet_another_file.txt'} {'yet_another_file.txt'} {'you_guessed_it_another_file.txt'} {'you_guessed_it_another_file.txt'} {'you_guessed_it_another_file.txt'}
for ii = 1:numel(file_number)
current_file_name = all_file_names{ii}
end
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'a_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'yet_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'
current_file_name = 'you_guessed_it_another_file.txt'

Sign in to comment.

More Answers (0)

Products


Release

R2020a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!