Reputation: 7143

How to move first element to the end of array

What is the best way to move the first element of the array till the end of this same array?

ie: [a,b,c,d]

"Some operation"

result: [b,c,d,a]

What should this "Some operation" be?

Upvotes: 22

Answers (4)

Reputation: 5588

    result=[a,b,c,d]
#first add first char at last in array
    result << result[0]
#remove first character from array
    result.shift

Upvotes: 1

Reputation: 160551

As @sawa says, use rotate. In other/older languages we'd do something like:

ary.push(ary.shift)

or wire up something by splitting/slicing the array in multiple steps.

The above is useful for a left-shift of the array. Reversing the direction is:

ary.unshift(ary.pop)

which is occasionally useful, along with the above, for simulating bit-twiddling at the binary level.

Upvotes: 3

Reputation: 118261

Yes possible using Array#shift

a = [1,2,7,4]
a << a.shift
a # => [2, 7, 4, 1]

Upvotes: 5

Reputation: 168081

[a,b,c,d].rotate(1)

Upvotes: 54