I was looking for a way to create an array like:
[[1,1], [1,2], [1,3]
[2,1], [2,2], [2,3]
[3,1], [3,2], [3,3]]
For now I came up with this solution:
w=3 # or any int
h=3 # or any int
array = []
iw=1
while iw<=w do
ih=1
while ih <=h do
array<<[iw, ih]
ih+=1
end#do
iw+=1
end#do
But, I'm sure there must be a quicker way..? This takes 1.107 seconds... (w=1900; h=1080) Regards
EDIT: I should've noticed that I'm stuck with 1.8.6..
Use either product or repeated_permutation:
[1, 2, 3].product([1, 2, 3]) # => [[1, 1], ...
# or
[1, 2, 3].repeated_permutation(2) # => [[1, 1], ...
product is in Ruby 1.8.7+ (accepts a block in 1.9.2+) while repeated_permutation in 1.9.2+. For other versions of Ruby, you can use include my backports gem and include 'backports/1.9.2/array/repeated_permutation' or include 'backports/1.8.7/array/product'.
backports. You'll be at basically at the level of 1.8.7 with a lot of goodies of 1.9, and in a few weeks I'm enabling some features of 2.0 tooThis is similar to @nicooga's answer, but I would use a range instead of manually creating the array (ie so you do not have to type each number for larger arrays).
range = (1..3).to_a
range.product(range)
#=> [[1, 1], [1, 2], [1, 3], [2, 1], [2, 2], [2, 3], [3, 1], [3, 2], [3, 3]]
There is a faster way:
> [1,2,3].product([1,2,3])
=> [[1, 1], [1, 2], [1, 3], [2, 1], [2, 2], [2, 3], [3, 1], [3, 2], [3, 3]]
