Ruby string strip defined characters

In Python, we can use the .strip() method of a string to remove lea开发者_如何转开发ding or trailing occurrences of chosen characters:

>>> print " (Removes (only) leading & trailing brackets & ws ) ".strip(" ()")
'Removes (only) leading & trailing brackets & ws'

How do we do this in Ruby? Ruby's strip method takes no arguments and strips only whitespace.

There is no such method in ruby, but you can easily define it like:

def my_strip(string, chars)
  chars = Regexp.escape(chars)
  string.gsub(/\A[#{chars}]+|[#{chars}]+\z/, "")
end

my_strip " [la[]la] ", " []"
#=> "la[]la"

"[[ ] foo [] boo ][ ]".gsub(/\A[ \[\]]+|[ \[\]]+\Z/,'') 
=> "foo [] boo"

Can also be shortenend to

"[[ ] foo [] boo ][ ]".gsub(/\A[][ ]+|[][ ]+\Z/,'') 
=> "foo [] boo"

There is no such method in ruby, but you can easily define it like:

class String
    alias strip_ws strip
    def strip chr=nil
        return self.strip_ws if chr.nil?
        self.gsub /^[#{Regexp.escape(chr)}]*|[#{Regexp.escape(chr)}]*$/, ''
    end
end

Which will satisfy the requested requirements:

> "[ [] foo [] boo [][]] ".strip(" []")
 => "foo [] boo"

While still doing what you'd expect in less extreme circumstances.

>  ' _bar_ '.strip.strip('_')
 => "bar"

nJoy!

Try the gsub method:

irb(main):001:0> "[foo ]".gsub(/\As+[/,'')
=> "foo ]"

irb(main):001:0> "foo ]".gsub(/s+]\Z/,'')
=> "foo"

etc.

You can use: str.chomp('.') that works for trailing characters and you can reverse the string for leading characters: str.reverse.chomp('.').reverse

To do both at once you can: str.chomp('.').reverse.chomp('.').reverse

Note: chomp removes only one occurrence by default

Ruby now includes full support for stripping with

lstrip: Strips only leading part of string rstrip: Strips only ending part of string strip: Strips both leading and ending of string

Try the String#delete method: (avaiable in 1.9.3, not sure about other versions)

Ex:

    1.9.3-p484 :003 > "hehhhy".delete("h")
     => "ey"