如何在Ruby的循环中跳过几次迭代? [英] how to skip a few iterations in a loop in Ruby?

问题描述

假设我有下面的 C 代码

Suppose I have the C code below

for(i = 0; i < 10; i++){
    printf("Hello");
    if(i == 5){
        a[3] = a[2] * 2;
        if(a[3] == b)
            i = a[3];           //Skip to index = a[3]; depends on runtime value
    }
}

如何转换为 Ruby?我知道我们可以使用 next 跳过一次迭代，但我必须根据条件值跳过几次迭代，而且我不知道在运行前要跳过多少次迭代?

How to convert to Ruby? I know we can skip one iteration using next, but I have to skip a few iterations depending on conditional value and I don't know how many iterations to skip before runtime?

这是我实际正在处理的代码(正如 Coreyward 提到的):

Here is the code I am actually working on (as mentioned by Coreyward):

我正在数组中寻找值差异小于 0.1 的直线"(小于 0.1 将被视为直线").范围必须大于 50 才能被视为长行".在我找到行范围 [a,b] 后，我想跳过迭代到上限 b，这样它就不会从 a+1 重新开始，它会从 b+1 开始寻找新的直线"

I am looking for "straight line" in the array that the values differs less than 0.1(less than 0.1 will considered as a "straight line"). The range has to be longer than 50 to be considered as a long "line". After I find the line range [a,b], i wanna skip the iterations to upper limit b so it would not start again from a+1, and it will start to find new "straight line" from b+1

for(i=0; i<arr.Length; i++){
  if(arr[i] - arr[i + 50] < 0.1){
    m = i;                                   //m is the starting point
    for(j=i; j<arr.Length; j++){             //this loop makes sure all values differs less than 0.1
      if(arr[i] - arr[j] < 0.1){
        n = j;
      }else{
        break;
      }
    }
    if(n - m > 50){                          //Found a line with range greater than 50, and store the starting point to line array
      line[i] = m
    }
    i = n                                     //Start new search from n
  }

}

推荐答案

另一种方法是使用 枚举器 类:

Another way is using the enumerator class:

iter = (1..10).to_enum
while true
  value = iter.next
  puts "value is #{value.inspect}"
  if value == 5
    3.times {value = iter.next}
  end
end

给予

value is 1
value is 2
value is 3
value is 4
value is 5
value is 9
value is 10
StopIteration: iteration reached at end
        from (irb):15:in `next'
        from (irb):15
        from C:/Ruby19/bin/irb:12:in `<main>'

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