ls syntax for output variable with flags

Question

DLR 2024-4-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2106396-ls-syntax-for-output-variable-with-flags

评论： Voss 2024-4-13

I am trying to use the ls command to get a variable containing a single-column list of filenames (strings, char, cell, etc--doesn't really matter), replacing an older approach that leaves behind a text file every time I use it:

unix(horzcat('ls -1 ','*.mat',' > filelist'));
filenames = textread('filelist','%s');

It seems like it should be possible to do this, based on the following from the Matlab ls documentation:

list = ls(___) returns the names of all the files and folders in the current folder that match the specified name. You can specify list with any of the arguments in the previous syntaxes.

and Tips (on the same documentation page):

To further modify the results of the ls command on UNIX platforms, you can add any flags that the operating system supports. For example, ls -c displays files by timestamp and ls -d displays only directories. For more information, see the UNIX ls documentation.

But there are no examples of the correct syntax to use with flags to direct results into a variable. Anyone know the right syntax here? Thanks!

Here's what I've tried so far:

If I use a flag without parentheses or specifying an output variable, it sends exactly what I want (I think) to the command window:

>> ls -1 *.mat
20240229_PRC_Flume_run1.mat
20240229_PRC_Flume_run1b.mat
20240229_PRC_Flume_run1c.mat
20240229_PRC_Flume_run2.mat
20240229_PRC_Flume_run3.mat
20240229_PRC_Flume_run4.mat
20240229_PRC_Flume_seis-hammer-test.mat
20240229_PRC_Flume_tap-test.mat
20240301_PRC_Flume_hammer-test-2.mat
20240301_PRC_Flume_run10.mat
20240301_PRC_Flume_run11.mat
20240301_PRC_Flume_run5-20k.mat
20240301_PRC_Flume_run5-40k.mat
20240301_PRC_Flume_run6.mat
20240301_PRC_Flume_run7.mat
20240301_PRC_Flume_run8.mat
20240301_PRC_Flume_run9.mat

When I use parentheses and an output variable but no flags, it returns a single char array with all filenames:

>> list = ls('*.mat')
list =
'20240229_PRC_Flume_run1.mat		20240229_PRC_Flume_run4.mat		20240301_PRC_Flume_run11.mat		20240301_PRC_Flume_run8.mat
'20240229_PRC_Flume_run1b.mat		20240229_PRC_Flume_seis-hammer-test.mat	20240301_PRC_Flume_run5-20k.mat		20240301_PRC_Flume_run9.mat
'20240229_PRC_Flume_run1c.mat		20240229_PRC_Flume_tap-test.mat		20240301_PRC_Flume_run5-40k.mat
'20240229_PRC_Flume_run2.mat		20240301_PRC_Flume_hammer-test-2.mat	20240301_PRC_Flume_run6.mat
'20240229_PRC_Flume_run3.mat		20240301_PRC_Flume_run10.mat		20240301_PRC_Flume_run7.mat
'
>> whos list
  Name      Size             Bytes  Class    Attributes
  list      1x523             1046  char               
>> list = ls -1 *.mat
 'list = ls -1 *.mat
               ↑
'Invalid use of operator.
 
>> list = ls(-1 *.mat)
 'list = ls(-1 *.mat)
               ↑
'Invalid use of operator.
 
>> list = ls([-1 *.mat])
 'list = ls([-1 *.mat])
                ↑
'Invalid use of operator.
 
>> list = ls(-1 *mat)
'Unrecognized function or variable ''mat''.
 
>> list = ls('-1' '*mat')
 'list = ls(''-1'' ''*mat'')
                ↑
'Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.
 
>> list = ls('-1 *mat')
'Error using ls (line 47)
'ls: invalid option --
'usage: ls [-@ABCFGHILOPRSTUWabcdefghiklmnopqrstuvwxy1%,] [--color=when] [-D format] [file ...]
>> list = ls('-1 ','*.mat')
'Error using ls (line 47)
'ls: invalid option --
'usage: ls [-@ABCFGHILOPRSTUWabcdefghiklmnopqrstuvwxy1%,] [--color=when] [-D format] [file ...]
 

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Voss 2024-4-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2106396-ls-syntax-for-output-variable-with-flags#answer_1440676

编辑：Voss 2024-4-13

在 MATLAB Online 中打开

% save a bunch of mat files
x = 1;
for i = 1:26
    save([char(64+i) '.mat'],'x');
end
% use multiple arguments to ls
list = ls('-1','*.mat')
list = 
    'A.mat
     B.mat
     C.mat
     D.mat
     E.mat
     F.mat
     G.mat
     H.mat
     I.mat
     J.mat
     K.mat
     L.mat
     M.mat
     N.mat
     O.mat
     P.mat
     Q.mat
     R.mat
     S.mat
     T.mat
     U.mat
     V.mat
     W.mat
     X.mat
     Y.mat
     Z.mat
     '

2 个评论
显示无隐藏无

DLR 2024-4-13

You're kidding me -- I was going to say I had already tried that (and just edited my post to include the error this produces), but just realized that I left a space in '-1 '. This works. Thank you so much!