String string position move

Regular string string position movement

1. Customizing a regular string string

" 1,2,3,x,y,4,5 ";

2. Splitting NUMSTR strings by commas

string[] Nums = Numstr.split (",");

3. Convert the Nums array to list

list<string> numlist = arrays.aslist (nums);

4. Get the subscript for X in list here index: 3

int index = numlist.indexof ("x");

5. Move x Backward by one

Collections.rotate (numlist.sublist (index, index+1+1),-1);

6. Convert list to string string here output Numstr: 1,2,3,y,x,4,5

Numstr = String.Join (",", numlist);

use of the 7.rotate method

RotateMethod requires a parameterdistance, the method adds aListHow many lengths are rotateddistance。 If there is a sequence columnlistIs[a,b,c,d], call methodCollections.rotate(list, 1)After that get thelistIt changed to[d,a,b,c]。
When this method is called, the locationiThe element on will become a position(i - distance) mod list.size()The Elements,0 <= i < list.size()。distanceCan be positive, 0, negative. Positive numbers rotate forward (the direction in which the subscript value becomes larger), and negative numbers represent backward rotation. Calling methodsCollections.rotate(list, -1)After that get thelistIt changed to[b,c,d,a]。

This method is often List used in conjunction with a subList method that moves list one or more elements without destroying the order of the remaining elements. For example, to list move an element of a position j forward to a k position. (Set the distance to move is d ( d >= 0 ) k = j + d + 1 ,).

Collections.rotate(list.subList(j, k+1), -1);

To raise a chestnut, for example [a,b,c,d,e] , b move an element forward three positions

Collections.rotate(list.subList(1, 5), -1);

After the call list is [a,c,d,e,b] received.

8.rotate explanation

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String string position move