find function using wildcards

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sermet OGUTCU 2021-9-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1455334-find-function-using-wildcards

评论： Rik 2021-9-17

fileID = fopen(full_file_name);
header = textscan(fileID, '%[^,\n]');
fclose(fileID);
end_of_header_line=find(contains(header{1,1},'*  '));

Here, I find all line numbers of header includes any * with two spaces or more. I need to modify the last part of the above codes to find all line numbers includes * with two spaces and following four digit numbers such as;

* 2021

For example header includes:

/*     GeoForschungsZentrum Potsdam                                             
/*                                                                              
/*                                                                              
*  2021  3 28  0  0  0.00000000    

The line numbers (end_of_header_line) produced from above codes includes all 4 lines. What I need to find only the last line.

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Answer 1

Rik 2021-9-17

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1455334-find-function-using-wildcards#answer_789539

在 MATLAB Online 中打开

You can use the patterns introduced in R2020b:

str={'/*     GeoForschungsZentrum Potsdam                                             '
'/*                                                                              '
'/*                                                                              '
'*  2021  3 28  0  0  0.00000000  '};
pat="*"+whitespacePattern(2,inf)+digitsPattern(1);
contains(str,pat)
ans = 4×1 logical array
   0
   0
   0
   1

Alternatively you can use regular expressions, which are not much harder to use.

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sermet OGUTCU 2021-9-17

Dear @Rik, my matlab version is R2019a. If it is possible, could you show me the another way that will be worked in this version?

Rik 2021-9-17

在 MATLAB Online 中打开

When you posted your question you had the opportunity to enter your release. Please do so next time. As you can see it is sometimes relevant.

str={'/*     GeoForschungsZentrum Potsdam                                             '
'/*                                                                              '
'/*                                                                              '
'*  2021  3 28  0  0  0.00000000  '};
pat=['\*',...       % a literal *
    '\s\s','\s*',...% two whitespace characters, followed by 0 or more
    '\d'];          % any digit
pos=regexp(str,pat) %regexp returns the position of a match
pos = 4×1 cell array
    {0×0 double}
    {0×0 double}
    {0×0 double}
    {[       1]}
%The legacy syntax of cellfun is the only case where it is faster than a
%loop. However, it doesn't work properly with all data types.
logical(cellfun('prodofsize',pos))
ans = 4×1 logical array
   0
   0
   0
   1