How to iterate through an array starting from the

2020-02-26 03:51发布

I came with below solution but I believe that must be nicer one out there ...

array = [ 'first','middle','last']

index = array.length
array.length.times { index -= 1; puts array[index]}

6条回答
Viruses.
2楼-- · 2020-02-26 04:06

In case you want to iterate through a range in reverse then use:

(0..5).reverse_each do |i|
  # do something
end
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爷的心禁止访问
3楼-- · 2020-02-26 04:12

If you want to achieve the same without using reverse [Sometimes this question comes in interviews]. We need to use basic logic.

  1. array can be accessed through index
  2. set the index to length of array and then decrements by 1 until index reaches 0
  3. output to screen or a new array or use the loop to perform any logic.

        def reverseArray(input)
          output = []
          index = input.length - 1 #since 0 based index and iterating from 
          last to first
    
          loop do
            output << input[index]
            index -= 1
            break if index < 0
          end
    
          output
        end
    
        array = ["first","middle","last"]
    
        reverseArray array #outputs: ["last","middle","first"]
    
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Emotional °昔
4楼-- · 2020-02-26 04:16

Ruby is smart

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }
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你好瞎i
5楼-- · 2020-02-26 04:18

In a jade template you can use:

for item in array.reverse()
   item
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叼着烟拽天下
6楼-- · 2020-02-26 04:24

You can even use a for loop

array = [ 'first','middle','last']
for each in array.reverse do
   print array
end

will print

last
middle
first
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▲ chillily
7楼-- · 2020-02-26 04:27
array.reverse.each { |x| puts x }
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