How to see if a string ends with one of multiple characters

问题

I have this statement:

string_tokens[-1].ends_with?(",") || string_tokens[-1].ends_with?("-") || string_tokens[-1].ends_with?("&")

I would like to put all the tokens (",", "-", "&") into a constant and simplify the above to ask, "does the string end with any of these characters", but I'm not sure how to do that.

回答1:

Yes.

CONST = %w(, - &).freeze
string_tokens[-1].end_with?(*CONST)

Usage:

'test,'.end_with?(*CONST)
#=> true
'test&'.end_with?(*CONST)
#=> true
'test-'.end_with?(*CONST)
#=> true

You use * (splat operator) to pass multiple args to the String#end_with?, because it accepts multiple.

回答2:

You could also use a regex :

chars = %w(, - &)
ENDS_WITH_CHAR = Regexp.new("["+chars.map{|s| Regexp.escape(s)}.join+']\z')
"abc-" =~ ENDS_WITH_CHAR
# or with Ruby 2.4
"abc-".match? ENDS_WITH_CHAR

回答3:

str = 'hello-'

',-&'.include? str[-1]
  #=> true

',$&'.include? str[-1]
  #=> false

来源：https://stackoverflow.com/questions/42537226/how-to-see-if-a-string-ends-with-one-of-multiple-characters