如何在ruby中删除所有非数字符号（逗号和破折号除外）

Question

I meet some hard task for me. I has a string which need to parse into array and some other elements. I have a troubles with REGEXP so wanna ask help.

I need delete from string all non-digits, except commas (,) and dashes (-)

For example:

"!1,2e,3,6..-10" => "1,2,3,6-10"
"ffff5-10...." => "5-10"
"1.2,15" => "12,15"

and so.

Answer 1

[^0-9,-]+

This should do it for you.Replace by empty string .See demo.

https://regex101.com/r/vV1wW6/44

Answer 2

We must have at least one non-regex solution:

def keep_some(str, keepers)
  str.delete(str.delete(keepers))
end

keep_some("!1,2e,3,6..-10", "0123456789,-")
  #=> "1,2,3,6-10" 
keep_some("ffff5-10....", "0123456789,-")
  #=> "5-10"
keep_some("1.2,15", "0123456789,-")
  #=> "12,15"

Answer 3

"!1,2e,3,6..-10".gsub(/[^\d,-]+/, '') # => "1,2,3,6-10"

Answer 4

Use String#gsub with a pattern that matches everything except what you want to keep, and replace it with the empty string. In a reguar expression, the negated character class [^whatever] matches everything except the characters in the "whatever", so this works:

a_string.gsub /[^0-9,-]/, ''

Note that the hyphen has to come last, as otherwise it will be interpreted as a range indicator.

To demonstrate, I put all your "before" strings into an Array and used Enumerable#map to run the above gsub call on all of them, producing an Array of the "after" strings:

["!1,2e,3,6..-10", "ffff5-10....", "1.2,15"].map { |s| s.gsub /[^0-9,-]/, '' }

# => ["1,2,3,6-10", "5-10", "12,15"]