Help with extracting part of a string

Question

aurc89 2014-9-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/156298-help-with-extracting-part-of-a-string

编辑： Stephen23 2018-11-14

I have the string "2DVIS_data_08_40fs", and I want to extract the numbers included between the last underscore '_' and the last two letters 'fs', in this case 40. Given the string "2DVIS_data_08_120fs", I want as output 120 and so on. How can I do this? thanks

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

Chad Greene 2014-9-26

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/156298-help-with-extracting-part-of-a-string#answer_152995

在 MATLAB Online 中打开

Guillame's answer is best, and it's probably good to learn how to use the power of regexp. But if you want a more intuitive-for-beginners approach, find the indices of the underscores, find the indices of fs, and then return everything between them:

somestring = '2DVIS_data_08_40fs'; 
underscore_indices = strfind(somestring,'_'); 
fs_indices = strfind(somestring,'fs'); 
yourNumber = str2double(somestring(underscore_indices(end)+1:fs_indices(end)-1))

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

aurc89 2014-9-28

Thank you, since I'm a beginner this is easier for me

请先登录，再进行评论。

Answer 2

Stephen23 2014-9-26

7
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/156298-help-with-extracting-part-of-a-string#answer_153015

编辑：Stephen23 2014-9-27

在 MATLAB Online 中打开

Use regexp .

Given a literal interpretation of your statement "extract the numbers included between the last underscore '_' and the last two letters 'fs'", this could be done using the following regexp match string:

>>A = {'2DVIS_data_08_120fs','2DVIS_data_08_40fs'};
>>B = regexp(A,'(?<=_)\d+(?=fs$)','once','match')
B = 
  '120'    '40'

This match string locates one or more digits located between an '_' and the last two characters of the string (which must be 'fs'). If the strings are always of the same format, then matching of the last two characters would be enough.

2 个评论
显示无隐藏无

Chad Greene 2014-9-26

nice. :)

aurc89 2014-9-28

Thanks Stephen!

请先登录，再进行评论。

Answer 3

Guillaume 2014-9-26

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/156298-help-with-extracting-part-of-a-string#answer_152991

在 MATLAB Online 中打开

Use regexp, you haven't explained the pattern in great details, the following may be what you want:

elems = regexp(s, '_(\d+)_[^_]*(..)$', 'tokens', 'once');
number = str2double(elems{1});
string = elems{2};

It will match any pattern with _, followed by 1 or more digit (an integer), followed by _, followed by any 0 or more characters not including _, followed by two characters at the end of the string. It extracts the integer and the last two characters.