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Ruby: How to iterate over a range, but in set increments?

开发者 https://www.devze.com 2023-01-28 21:51 出处:网络
So I\'m iterating over a range like so: (1..100).each do |n| # n = 1 # n = 2 # n = 3 # n = 4 # n = 5 end But what I\'d like to do is iterate b开发者_开发技巧y 10\'s.

So I'm iterating over a range like so:

(1..100).each do |n|
    # n = 1
    # n = 2
    # n = 3
    # n = 4
    # n = 5
end

But what I'd like to do is iterate b开发者_开发技巧y 10's.

So in stead of increasing n by 1, the next n would actually be 10, then 20, 30, etc etc.


See http://ruby-doc.org/core/classes/Range.html#M000695 for the full API.

Basically you use the step() method. For example:

(10..100).step(10) do |n|
    # n = 10
    # n = 20
    # n = 30
    # ...
end


You can use Numeric#step.

0.step(30,5) do |num|
  puts "number is #{num}"
end
# >> number is 0
# >> number is 5
# >> number is 10
# >> number is 15
# >> number is 20
# >> number is 25
# >> number is 30


Here's another, perhaps more familiar-looking way to do it:

for i in (0..10).step(2) do
    puts i
end


rng.step(n=1) {| obj | block } => rng

Iterates over rng, passing each nth element to the block. If the range contains numbers or strings, natural ordering is used. Otherwise step invokes succ to iterate through range elements. The following code uses class Xs, which is defined in the class-level documentation.

range = Xs.new(1)..Xs.new(10)
range.step(2) {|x| puts x}
range.step(3) {|x| puts x}

produces:

1 x
3 xxx
5 xxxxx
7 xxxxxxx
9 xxxxxxxxx
1 x
4 xxxx
7 xxxxxxx
10 xxxxxxxxxx

Reference: http://ruby-doc.org/core/classes/Range.html

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