# Anyone use .uniq!?

could anyone by chance give me a working example of the .uniq! method?
i’ve been trying all day. any help would be much appreciated!

jon

found this in the API docs:
http://www.rubycentral.com/ref/ref_c_array.html#uniq_oh

make sure you’re using it on an array, and remember that if no
duplicates are found, the result is nil.

dorian

Dorian M. wrote:

i’ve been trying all day. any help would be much appreciated!
irb(main):001:0> a = [ 1, 2, 3, 3, 4, 5]
=> [1, 2, 3, 3, 4, 5]
irb(main):002:0> a.uniq
=> [1, 2, 3, 4, 5]
irb(main):003:0> a
=> [1, 2, 3, 3, 4, 5]
irb(main):004:0> a.uniq!
=> [1, 2, 3, 4, 5]
irb(main):005:0> a
=> [1, 2, 3, 4, 5]
irb(main):006:0> a.uniq!
=> nil

Ray

I missed an important bit

=> [1, 2, 3, 3, 4, 5]
irb(main):004:0> a.uniq!
=> [1, 2, 3, 4, 5]
irb(main):005:0> a
=> [1, 2, 3, 4, 5]
irb(main):006:0> a.uniq!
=> nil
irb(main):007:0> a
=> [1, 2, 3, 4, 5]

Ray

On 3/28/06, Ray B. [email protected] wrote:

=> [1, 2, 3, 4, 5]

Ray

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This is exactly according to the documentation. compact and compact!
work
the same way-

## ri uniq ------------------------------------------------------------- Array#uniq array.uniq -> an_array

`````` Returns a new array by removing duplicate values in _self_.

a = [ "a", "a", "b", "b", "c" ]
a.uniq   #=> ["a", "b", "c"]
``````

## ri uniq! ------------------------------------------------------------ Array#uniq! array.uniq! -> array or nil

`````` Removes duplicate elements from _self_. Returns +nil+ if no changes
are made (that is, no duplicates are found).

a = [ "a", "a", "b", "b", "c" ]
a.uniq!   #=> ["a", "b", "c"]
b = [ "a", "b", "c" ]
b.uniq!   #=> nil
``````

Regards,
Nick

2006/3/27, Jon [email protected]:

could anyone by chance give me a working example of the .uniq! method?
i’ve been trying all day. any help would be much appreciated!

array = %w(a a)
puts array
[“a”, “b”]
array.uniq!
puts array
[“a”]

#uniq! makes the receiver keep unique values. Values are compared
using #== (or is it #equal?). #uniq! is equivalent to this loop:

temp = Array.new
%w(a a).each do |value|
temp << value unless temp.include?(value)
end

Of course, this loop returns a NEW array, whereas #uniq! changes the
receiver (notice ! at the end ?)

Hope that helps !

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