@message_to = '[email protected]'
@cleaned = @message_to.match(/^(.*)+@/)
@cleaned is returning bob@, where I want it to return just bob. Am I doing the regex right with ruby?
Thanks
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2I think regex and email addresses are some sort of gateway-drug-combination for developers. This is a worthy SO question and discussion about the pair: Why are people using regexp for email and other complex validation?the Tin Man– the Tin Man2011-02-28 04:24:21 +00:00Commented Feb 28, 2011 at 4:24
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@the Tin Man: All programmers are really failed wizards that would rather be casting spells, regular expressions smell like incantations so there's a natural affinity for them.mu is too short– mu is too short2011-03-01 06:57:15 +00:00Commented Mar 1, 2011 at 6:57
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@mu is too short, LOL. Yes, very possibly. I always thought it was a macho thing.the Tin Man– the Tin Man2011-03-01 23:13:10 +00:00Commented Mar 1, 2011 at 23:13
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6 Answers
No need much regular expression
>> @message_to = "[email protected]"
=> "[email protected]"
>> @message_to.split("@",2)
=> ["bob", "google.com"]
>> @message_to.split("@",2)[0] if @message_to["@"]
=> "bob"
>>
2 Comments
mu is too short
+1: People do tend to get fixated on using regexes for everything, basic string mangling shouldn't be overlooked.
the Tin Man
+1 It's the old "when you have a hammer everything looks like a nail." situation. Regex is a powerful tool, but I find it usually contributes to confusing code, rather than making it clearer, cleaner, and more maintainable.
You want this:
@cleaned = @message_to.match(/^(.*)+@/)[1]
match returns a MatchData object and the string version of that is the entire match, the captured groups are available starting at index 1 when you treat the MatchData as an array.
I'd probably go with something more like this though:
@cleaned = @message_to.match(/^([^@]+)@/)[1]
Comments
An even shorter code than mu_is_too_short would be:
@cleaned = @message_to[/^([^@]+)@/, 1]
The String#[] method can take a regular expression.
Comments
The simplest RegEx I got to work in the IRB console is:
@message_to = '[email protected]'
@cleaned = @message_to.match(/(.+)@/)[1]
Also from this link you could try:
@cleaned = @message_to.match(/^(?<local_part>[\w\W]*?)@/)[:local_part]
Comments
The most obvious way to adjust your code is by using a forward positive assertion. Instead of saying "match bob@" you're now saying "match bob, when followed by a @"
@message_to = '[email protected]'
@cleaned = @message_to.match(/^(.*)+(?=@)/)
A further point about when to use and not to use regexes: yes, using a regex is a bit pointless in this case. But when you do use a regex, it's easier to add validation as well:
@cleaned = @message_to.match(/^(([-a-zA-Z0-9!#$%&'*+\/=?^_`{|}~]+.)*[-a-zA-Z0-9!#$%&'*+\/=?^_`{|}~]+(?=@)/)
(and yes, all those are valid in email-adresses)
1 Comment
the Tin Man
"But when you do use a regex, it's easier to add validation as well", except those don't really cover all the corner cases for email addresses, or test whether it's a live address, which is the real-world test. Perl's Mail::RFC822::Address module has the
make_rfc822re function which takes a pretty good shot at generating a RFC-compliant regex. This is a pertinent discussion: stackoverflow.com/q/211842/128421