how to read text files using regular expressions

Question

Li Xue 2017-7-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/348381-how-to-read-text-files-using-regular-expressions

回答： Walter Roberson 2017-7-12

What is a fast way to read lines that matches some regular expressions from a text file? For example, read only the lines starting with integer, and split this line by spaces into a vector. I would like to use textscan, because it is very fast.

An example file looks like this:

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

Walter Roberson 2017-7-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/348381-how-to-read-text-files-using-regular-expressions#answer_273875

textscan is not able process regular expressions.

You can read the entire file in at one time using fileread, into a string. You can use regexp or regexprep to select portions of the string, for which you will probably need to use the options 'lineanchors' and 'dotexceptnewline'. You can then enter break the remaining up using text processing or you can pass the resulting string as the first parameter to textscan replacing the fid parameter.