what is dup?

[David Madden]

I am playing with an example in the ruby cookbook where a shuffle
function is added to the array class:

class Array

def shuffle!
each_index do |i|
j = rand(length-i) + i
self[j], self = self, self[j]
end
end

def shuffle
dup.shuffle!
end

end

What I don't understand is the line "dup.shuffle!"

What is the dup object?

Dave.

 

[Wilson Bilkovich]

I am playing with an example in the ruby cookbook where a shuffle
function is added to the array class:

class Array

def shuffle!
each_index do |i|
j = rand(length-i) + i
self[j], self = self, self[j]
end
end

def shuffle
dup.shuffle!
end

end

What I don't understand is the line "dup.shuffle!"

What is the dup object?

dup returns a copy (duplicate) of the object. In the above code, it is
used to let you get back a shuffled copy of the Array, without
shuffling the original.

type:
ri Object#dup
for more info.

 

[David Madden]

dup returns a copy (duplicate) of the object. In the above code, it is
used to let you get back a shuffled copy of the Array, without
shuffling the original.

type:
ri Object#dup
for more info.

Thanks,

Dave.