正则表达式，忽略前面字符的结果

Question

I have a regex for matching URLs ((https?:\\/\\/)?[\\w-]+(\\.[\\w-]+)+\\.?(:\\d+)?(\\/\\S*)?) and it does the job, it works for what I want. However it will also match the domain for an e-mail when I don't want it to.

Currently matchs:

• http://www.foo.bar
• foo.bar
• website: foo.bar (matches the foo.bar part)
• info@ foo.bar (matches the foo.bar part)

I don't want it to match that last one, so it only matches the first three. I tried adding (?!=@) to the front but that didn't do it. How can I get it to ignore results preceded with an @ symbol?

Answer 1

Add anchors to your regex

^((https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/\S*)?)$

see the example http://regex101.com/r/lI8kZ6/1

Explantion

^ asserts the regex at the start of the line

$ asserts the regex at the end of the line

EDIT

If the urls are embedded within text use \\s to delemit the regex match strings as

(\s|^)((https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/\S*)?)\s

see the example

http://regex101.com/r/lI8kZ6/3

Answer 2

Anchors will only work if your string only consists of the URL you want to match. This is probably not the case.

Instead, what you really want is to match where there is space (or nothing) before the URL. Try:

(?:^|(?<=\s))YOUR REGEX HERE

This will check if there is nothing, or a space character, before the regex you already have.

Demo on regex101

Consider further adding (?=\\s|$) to the end of the regex, to ensure it doesn't match half a word.

Answer 3

^((https?:\/\/)?[\w-]+(\.[\w-]+)+\.?(:\d+)?(\/[\S]*)?)$

just add anchors to remove partial matching.Enable m or multliline flag.See demo.

http://regex101.com/r/sU3fA2/43