[英]Incrementing value with a ForEach loop to apply on each element
寻求有关数组和增量的帮助。
我有一个函数,它对数组中的每个新元素应用相同的样式,如下所示。
function SnakeBodyLeft(){
StorePositions.forEach(BodySnake => {
BodySnake.style.gridRowStart = (Initial_y + y);
BodySnake.style.gridColumnStart = (Initial_x + x)+1 ;
});
};
// this results in
StorePositions[0] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
StorePositions[1] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
StorePositions[2] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
And so on...
我想编写一个函数来执行上面显示的操作,但是为每个新元素增加值 +1 并保留第一个元素的初始值。 结果会是这样的:
StorePositions[0] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
StorePositions[1] = BodySnake.style.gridColumnStart = (Initial_x + x)+2
StorePositions[2] = BodySnake.style.gridColumnStart = (Initial_x + x)+3
StorePositions[3] = BodySnake.style.gridColumnStart = (Initial_x + x)+4
And so on....
我试图使 1 成为一个名为 i 的变量并增加它。 但是当我这样做时, i 的增量应用于数组中的所有元素,而不仅仅是新元素。
let i = 1++;
function SnakeBodyLeft(){
StorePositions.forEach(BodySnake=> {
BodySnake.style.gridRowStart = (Initial_y + y);
BodySnake.style.gridColumnStart = (Initial_x + x) + i ;
});
};
//this results in the incremented value being applied to all elements , not just the new ones .
StorePositions[0] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
StorePositions[1] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
StorePositions[2] = BodySnake.style.gridColumnStart = (Initial_x + x)+1
or
StorePositions[0] = BodySnake.style.gridColumnStart = (Initial_x + x)+2
StorePositions[1] = BodySnake.style.gridColumnStart = (Initial_x + x)+2
StorePositions[2] = BodySnake.style.gridColumnStart = (Initial_x + x)+2
基本上,随着索引的增长(0,1,2,3...),索引中每个新元素中的值 i 也应该增长。(0,1,2,3...)。
但我有点卡住了! 任何人都可以帮忙吗?
尝试这个
function SnakeBodyLeft(){
StorePositions.forEach((BodySnake, i)=> {
BodySnake.style.gridRowStart = (Initial_y + y);
BodySnake.style.gridColumnStart = (Initial_x + x) + i;
});
};
更新如果您需要从 1 开始递增,请改为执行此操作:
function SnakeBodyLeft(){
StorePositions.forEach((BodySnake, i)=> {
BodySnake.style.gridRowStart = (Initial_y + y);
BodySnake.style.gridColumnStart = (Initial_x + x) + (i + 1);
});
};
您可以像这样为 forEach 添加索引forEach(element, index) => { ... }
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