Nested Ruby List Generation

Question

I'm trying to generate a list that looks like this:

list = [[1, 1], [2, 2], [3, 3], [4, 4], ... [25, 25]]

Is there an easy way to accomplish this with something similar to range?

Update: Looks like .zip wins

.map time elapsed 1184.344 milliseconds
.zip time elapsed 706.23 milliseconds

Test:

beginning_time = Time.now
(1..2500000).map { |i| [i,i] }
end_time = Time.now
puts "Time elapsed #{(end_time - beginning_time)*1000} milliseconds"

beginning_time = Time.now
(1..2500000).zip 1..25
end_time = Time.now
puts "Time elapsed #{(end_time - beginning_time)*1000} milliseconds"

Jasdeep Singh · Accepted Answer · 2013-01-27 01:12:47Z

6

Try this:

(1..25).map { |i| [i,i] }

Output:

[[1, 1], [2, 2], [3, 3], [4, 4], [5, 5], [6, 6], [7, 7], [8, 8], [9, 9], [10, 10], [11, 11], [12, 12], [13, 13], [14, 14], [15, 15], [16, 16], [17, 17], [18, 18], [19, 19], [20, 20], [21, 21], [22, 22], [23, 23], [24, 24], [25, 25]]

answered Jan 27, 2013 at 1:12

Jasdeep Singh

3,3364 gold badges32 silver badges47 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Kyle · Accepted Answer · 2013-01-27 01:28:50Z

3

(1..25).zip 1..25
#=> [[1, 1], [2, 2], [3, 3], [4, 4] ...

answered Jan 27, 2013 at 1:28

Kyle

22.3k2 gold badges63 silver badges63 bronze badges

Comments

sawa · Accepted Answer · 2013-01-27 01:25:01Z

1

Try this:

Array.new(25){|i| [i+1, i+1]}

edited Jan 27, 2013 at 1:25

answered Jan 27, 2013 at 1:17

sawa

169k51 gold badges287 silver badges398 bronze badges

Comments

DigitalRoss · Accepted Answer · 2013-01-27 07:25:05Z

1

Ok, 2 hours late, and, just to be different...

[[*1..25], [*1..25]].transpose
# => [[1, 1], [2, 2], [3, 3], [4, 4], ...

...or...hehe...

([[*1..25]]*2).transpose

edited Jan 27, 2013 at 7:25

answered Jan 27, 2013 at 3:35

DigitalRoss

147k25 gold badges255 silver badges336 bronze badges

Collectives™ on Stack Overflow

Nested Ruby List Generation

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related