使用正则表达式匹配字符串

Question

I want to write a regular expression in a C++ program which checks if a string matches the following expression:

a word not containing '_' but it can contain number followed by

'_' followed by

three digits in a row (ie 047)

followed by '_' followed by

a string (can contain anything)

I have tried the following expression but it does seem to find the desired string as described above. I suspect the problem lies in the first part but I cannot detect it in order to modify properly:

static const wregex stringForm("([^_]?)_?(\\d{3})_(.+)");  

What is then the proper reg expression?

Answer 1

\b[^_]*?(_\d{3}.+?)?\b

A word ( \\b is word boundary, quantifiers are non-greedy). Zero or more characters that aren't _ ( [^_]*? ). Optionally ( (...)? ), the digit sequence you described ( _\\d{3} ) followed by one or more of any character ( .+? ).

Answer 2

你试过这个：

static const wregex stringForm("([a-zA-Z0-9]*_[0-9]{3}.*)");