Not being a regex expert, but finding the problem interesting, I looked around and found this interesting blog entry. Especially the syntax used there for defining the 2D regex looks appealing. The paper linked there might tell you more than me. Update from comment: Here is the link to the primary author’s page where you … Read more
(\w+)? and (\w*) both match the same (0..+inf word characters) However, there is a slight difference: In the first case, if this part of the regex matches “”, the capturing group is absent. In the second case, it is empty. In some languages, the former manifests as a null while the latter should always be … Read more
In order to remove anything but a specific text, you need to use .*(text_you_need_to_keep).* with . matching a newline. In Notepad++, use Find: .*(phone=\S*?digits=1).* Replace: $1 NOTE: . matches newline option must be checked. I use \S*? instead of .* inside the capturing pattern since you only want to match any non-whitespace characters as few … Read more
What about something like this? ^/([^/]+)/?(.*)$ I tested it with python and seems to work fine: >>> regex=re.compile(r’^/([^/]+)/?(.*)$’) >>> regex.match(‘/seattle’).groups() (‘seattle’, ”) >>> regex.match(‘/seattle/restaurant’).groups() (‘seattle’, ‘restaurant’)
Try a character class instead echo “$STRING” | egrep ‘[*]’
As Jim’s answer, use the /g modifier (in list context or in a loop). But beware of greediness, you dont want the .* to match more than necessary (and dont escape < = , they are not special). while($string =~ /<img\s+src=”https://stackoverflow.com/questions/2884549/(.*?)”/g ) { … }
A dash in a character class in a place where it cannot be interpreted as a range is interpreted as a literal dash. So the expression excludes the characters 0 to 9, a to z, A to Z, and -. That’s why there’s no syntax error. It’s probably a typo though. If the dash is … Read more
You could use grep -o then pipe through wc -l: $ echo “123 123 123” | grep -o 123 | wc -l 3
Your analysis of why the results are “ee” and “ebe” is completely accurate. The “/g” modifier causes the regex to match once, and then try to match again from where the last match stopped. The reason for the discrepancy (it doesn’t replace the empty string to the left of “a”) is that is because “*” … Read more