从中提取3的正则表达式是什么？

Question

I basically need to get the bit after the last pipe

"3083505|07733366638|3"

What would the regular expression for this be?

Answer 1

You can do this without regex. Here:

"3083505|07733366638|3".split("|").last
# => "3"

With regex: (assuming its always going to be integer values)

"3083505|07733366638|3".scan(/\|(\d+)$/)[0][0] # or use \w+ if you want to extract any word after `|`
# => "3"

Answer 2

Try this regex :

.*\|(.*)

It returns whatever comes after LAST | .

Answer 3

I would use split and last , but you could do

last_field = line.sub(/.+\|/, "")

That remove all chars up to and including the last pipe.

Answer 4

You could do that most easily by using String#rindex :

line = "3083505|07733366638|37"

line[line.rindex('|')+1..-1]
  #=> "37"

If you insist on using a regex:

r = /
    .*   # match any number of any character (greedily!)
    \|   # match pipe
    (.+) # match one or more characters in capture group 1
    /x   # extended mode

line[r,1]
  #=> "37"

Alternatively:

r = /
    .*   # match any number of any character (greedily!)
    \|   # match pipe
    \K   # forget everything matched so far
    .+   # match one or more characters
    /x   # extended mode

line[r]
  #=> "37"

or, as suggested by @engineersmnky in a comment on @shivam's answer:

r = /
    (?<=\|) # match a pipe in a positive lookbehind
    \d+     # match any number of digits
    \z      # match end of string
    /x      # extended mode

line[r]
  #=> "37"