belgoros
Regex question for hyphen match
I’m not a pro in using Regex and can’t figure out why the following behaviour happens, especially if we take into account the difference of matching in Javascript, Java, and Ruby (that’s why I’m a kind of stuck).
So I’d like to split a String input on one of the below characters:
- spaces
- underscores
- comma
- colon
- punctuation
- special characters
So I have the following code snippet in iex session:
String.split("testing, one, two car : carpet as java : javascript!!&@$%^& co-operation one_two 1 2", ~r/[\W-[_]|:]+/u, trim: true)
that returns:
["testing", "one", "two", "car", "carpet", "as", "java", "javascript", "co",
"operation", "one", "two", "1", "2"]
I had to substract underscore symbol from \W(any “non-word” character) as it includes it (a-zA-Z_).
As you see, there is still a problem with matching the hyphen in co-operation word.
Whatever I try, whenever I put - in the above regex, nothing works, - it just breaks the previously matching cases.
Any ideas? Thank you.
Marked As Solved
blatyo
Try this: ~r/([^\w\-]|_)+/u
Also Liked
blatyo
Oh, I finally understand what you’re doing. Use this regex instead.
String.split("co-operation tree_five one two 1 2 azerty : double:side", ~r/[^a-zA-Z0-9\-]+/u, trim: true)
#=> ["co-operation", "tree", "five", "one", "two", "1", "2", "azerty", "double",
"side"]
\W-[_] doesn’t mean subtract the underscore from the \W character class. There is no such supported operation in a regex like that which I’m aware of.
NobbZ
I’m not sure what you mean by “substracting the underscore”.
When I simply use ~r/[\W_]/ as the splitter, I get the same result as you with your more complicated regex. It seems as if it were already splitting on -. this way.
blatyo
If I understand your problem, I think you need to escape - in your character class. The reason is that - is used to defined ranges of characters. For example, ~r/[a-z]/ means all characters from a to z, not a, -, and z. You can escape characters in a character class, by using \. So, for the previous example, to get it to mean a, -, and z, you’d do ~r/[a\-z]/.
Hope that helps
peerreynders
In most flavors that support Unicode,
\wincludes many characters from other scripts. There is a lot of inconsistency about which characters are actually included. Letters and digits from alphabetic scripts and ideographs are generally included. Connector punctuation other than the underscore and numeric symbols that aren’t digits may or may not be included.
iex(1)> String.split("testing, co-operation tree_five one two 1 2 azerty : double:side schöner javascript!!&@$%^&", ~r/[^\p{L}\-]+/u, trim: true)
["testing", "co-operation", "tree", "five", "one", "two", "azerty", "double",
"side", "schöner", "javascript"]
You can match a single character belonging to the “letter” category with
\p{L}. You can match a single character not belonging to that category with\P{L}.
NobbZ
You missed the very first sentence of the article:
Character class subtraction is supported by the XML Schema, XPath, .NET (version 2.0 and later), and JGsoft regex flavors.
Neither Erlangs, nor Elixirs (which are basically the same) RegEx engine is in that list.
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Enabling companies to succeed by building software people love.
Categories:
Sub Categories:
Forums
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Practical resources that improve the lives of professional developers.
Develop your skills with books, videos, and courses.
Enabling companies to succeed by building software people love.
Courses that'll move you from confusion to "Aha, now I get it!"