Remove substring from the string - ruby

Question

I am just wondering if there is any method to remove string from another string?
Something like this:
class String
def remove(s)
self[s.length, self.length - s.length]
end
end

Answer 1

You can use the slice method:
a = "foobar"
a.slice! "foo"
=> "foo"
a
=> "bar"
there is a non '!' version as well. More info can be seen in the documentation about other versions as well:
http://www.ruby-doc.org/core/classes/String.html#method-i-slice-21

Answer 2

How about str.gsub("subString", "")
Check out the Ruby Doc

Answer 3

If it is a the end of the string, you can also use chomp:
"hello".chomp("llo") #=> "he"

Answer 4

If you only have one occurrence of the target string you can use:
str[target] = ''
or
str.sub(target, '')
If you have multiple occurrences of target use:
str.gsub(target, '')
For instance:
asdf = 'foo bar'
asdf['bar'] = ''
asdf #=> "foo "
asdf = 'foo bar'
asdf.sub('bar', '') #=> "foo "
asdf = asdf + asdf #=> "foo barfoo bar"
asdf.gsub('bar', '') #=> "foo foo "
If you need to do in-place substitutions use the "!" versions of gsub! and sub!.

Answer 5

Ruby 2.5+
If your substring is at the beginning of in the end of a string, then Ruby 2.5 has introduced the methods for this:
delete_prefix for removing a substring from the beginning of the string
delete_suffix for removing a substring from the end of the string

Answer 6

If you are using Rails there's also remove.
E.g. "Testmessage".remove("message") yields "Test".
Warning: this method removes all occurrences

Answer 7

If you are using rails or at less activesupport you got String#remove and String#remove! method
def remove!(*patterns)
patterns.each do |pattern|
gsub! pattern, ""
end
self
end
source: http://api.rubyonrails.org/classes/String.html#method-i-remove

Answer 8

If I'm interpreting right, this question seems to ask for something like a minus (-) operation between strings, i.e. the opposite of the built-in plus (+) operation (concatenation).
Unlike the previous answers, I'm trying to define such an operation that must obey the property:
IF c = a + b THEN c - a = b AND c - b = a
We need only three built-in Ruby methods to achieve this:
'abracadabra'.partition('abra').values_at(0,2).join == 'cadabra'.
I won't explain how it works because it can be easily understood running one method at a time.
Here is a proof of concept code:
# minus_string.rb
class String
def -(str)
partition(str).values_at(0,2).join
end
end
# Add the following code and issue 'ruby minus_string.rb' in the console to test
require 'minitest/autorun'
class MinusString_Test < MiniTest::Test
A,B,C='abra','cadabra','abracadabra'
def test_C_eq_A_plus_B
assert C == A + B
end
def test_C_minus_A_eq_B
assert C - A == B
end
def test_C_minus_B_eq_A
assert C - B == A
end
end
One last word of advice if you're using a recent Ruby version (>= 2.0): use Refinements instead of monkey-patching String like in the previous example.
It is as easy as:
module MinusString
refine String do
def -(str)
partition(str).values_at(0,2).join
end
end
end
and add using MinusString before the blocks where you need it.

Answer 9

here's what I'd do
2.2.1 :015 > class String; def remove!(start_index, end_index) (end_index - start_index + 1).times{ self.slice! start_index }; self end; end;
2.2.1 :016 > "idliketodeleteHEREallthewaytoHEREplease".remove! 14, 32
=> "idliketodeleteplease"
2.2.1 :017 > ":)".remove! 1,1
=> ":"
2.2.1 :018 > "ohnoe!".remove! 2,4
=> "oh!"
Formatted on multiple lines:
class String
def remove!(start_index, end_index)
(end_index - start_index + 1).times{ self.slice! start_index }
self
end
end