Start a loop from 1
I recently came upon the scary idea that Integer.count
loops in Ruby start from 0
and go to n-1
while playing with the Facebook Engineering puzzlers. I did the dirty fix of adding one to the block variable in the beginning so that it would start at one instead.
Is there a prettier way?
Example:
10.times do |n|
n += 1
puts n
end #=> 012345789
Ruby supports a number of ways of counting and looping:
1.upto(10) do |i|
puts i
end
>> 1.upto(10) do |i|
> puts i
| end #=> 1
1
2
3
4
5
6
7
8
9
10
There's also step
instead of upto
which allows you to increment by a step value:
>> 1.step(10,2) { |i| puts i } #=> 1
1
3
5
7
9
You could use a range:
(1..10).each { |i| puts i }
Ranges give you full control over the starting and ending indexes (as long as you want to go from a lower value to a higher value).
Try
(1..10).each do |i|
# ... i goes from 1 to 10
end
instead. It is also easier to read when the value of i
matters.
Old, but this might be something somebody's lookin for..
5.times.with_index(100){|i, idx| p i, idx};nil
#=>
0
100
1
101
2
102
3
103
4
104
There is of course the while
-loop:
i = 1
while i<=10 do
print "#{i} "
i += 1
end
# Outputs: 1 2 3 4 5 6 7 8 9 10