使用regex匹配Ruby子字符串，并像索引一样引用它

Posted 2021-02-27

# pass a Regexp into a String as if it were an Array index
 
 "cat"[/c/]
 #=> "c" 
 "cat"[/z/]
 #=> nil
 
 
# pass in an optional second argument, to return the content of the nth matching group
 
 re_phone = /(d{3})-(d{3})-(d{4})/
 "986-235-1001"[re_phone, 2]
 #=> "235"