How can make a regex using boost in c++?

Question

I need to create a regex that do the matching of 2 chars: & OR |.

The line of code is like this:

boost::regex EXPR( "[0-9][0-9][A-Za-z]" ) ;

If I type any string, I would see if the chars listed above are contained in it. How is possible to do this?

If the string is "asd" no match. If the string is "aaa&sss" match. If the string is "asss|sss" match. If the string is "asss&sfs|ssf" match. — user1056635
– user1056635, Commented Nov 20, 2011 at 18:04
So, in words, "some letters, followed by at least one & or |, followed by more letters or & or | ? — MSalters
– MSalters, Commented Nov 21, 2011 at 8:08

Merlyn Morgan-Graham · Accepted Answer · 2011-11-20 18:04:23Z

4

I wouldn't write a regular expression to match the characters & or |.

I'd use std::string::find - http://www.cplusplus.com/reference/string/string/find/

answered Nov 20, 2011 at 18:04

Merlyn Morgan-Graham

59.4k16 gold badges131 silver badges189 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

MSalters Over a year ago

If you're looking for either of two characters, use find_first_of.

Merlyn Morgan-Graham Over a year ago

@MSalters: Yeah when I was looking at find I thought the char* overload would do that, but now that I'm looking at it again, find_first_of makes more sense.

MSalters · Accepted Answer · 2011-11-21 08:10:47Z

1

Based on my interpretation of the grammar: [0-9A-Za-z]*[|&][0-9A-Za-z|&]*

answered Nov 21, 2011 at 8:10

MSalters

182k11 gold badges171 silver badges376 bronze badges

Comments

Geom · Accepted Answer · 2011-11-21 08:40:21Z

0

This should work: ".*?\Q|\E.*". Note that you need to double the backslashes, so it is:

string yourCharacter("|"); // or "&"
string rex(".*?\\Q"+yourCharacter+"\\E.*");

(all characters before and after are matched by this regex)

Here is an online tool to test regular expressions: http://gskinner.com/RegExr/

answered Nov 21, 2011 at 8:40

Geom

575 bronze badges

1 Comment

MSalters Over a year ago

Boost regex defaults to Perl syntax, which does have \Q...\E. But you don't need to escape characters inside a class, which is what you need here (One of two possible characters).

Collectives™ on Stack Overflow

How can make a regex using boost in c++?

3 Answers 3

2 Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related