Reading text file with variable name

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Abdulaziz Abutunis 2022-6-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1742650-reading-text-file-with-variable-name

编辑： Voss 2022-6-17

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

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Answer 1

Voss 2022-6-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1742650-reading-text-file-with-variable-name#answer_987775

在 MATLAB Online 中打开

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'

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Abdulaziz Abutunis 2022-6-17

Thank you very much

I found this works also

[num2str(file_number(i)),'.txt']

Voss 2022-6-17

编辑：Voss 2022-6-17

在 MATLAB Online 中打开

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'