数组逻辑：如何排列两个数组编号

Question

I have two arrays:

int array1 [] = {1,2,3,4,5,6,7}; [This array can grow to huge numbers]

int array2 [] = {1,2,3}; [Max it can have is 30 elements]

array1 should be the parent loop and will have more elements than array2. For example I have to arrange like below :

Expected result :
1-1
2-2
3-3
4-1
5-2
6-3
7-1

How can I proceed?

Answer 1

You don't need a nested loop in this case; all you need is proper use of the modulus operator.

for (int i = 0; i < array1.length; i++) {
  System.out.println(array1[i] + "-" + array2[i % array2.length]);
}

The reason this works is that the modulus operator maps very nicely to your problem. The operation you're trying to perform requires repeatedly iterating through a list ( array2 ) and wrapping back to the beginning. The modulus operator is, in essence, a "wrapping" operator; thinking incrementally, it allows you to go back to 0 every time you reach a certain number (in this case, the size of array2 ).

Answer 2

So you have two sets, you want to loop through each element of the larger set (array1) and for each element of the set print the element, and the next element of set2 (array2).

I used an enhanced for loop , it loops over each element, and then modulus witch effectively limits i to be less than the length of set2. (remainder must be less than 3 if dividing by 3)

This allows us to add one to i using i++ and be assured that it will always loop back around to the first element as if the value were on a spinner .

  int i = 0;
  for( int value : array1 ) {
     System.out.print( value + "-" + array2[i++ % array2.length] );
  }