Question

我需要根据数组的长度创建一个字符串值。

var array = ["left", "right", "top", "bottom"];
//list contain array of Object
 list.forEach((po) => {

//for example if the length of the list is 10. i need to generate the string for each loop like this 

// "left0"   for 1 loop i need this value 
// "right0"  for 2 loop i need this value
// "top0"      for 3 loop i need this value
// "bottom0"   for 4 loop i need this value

// "left1"     for 5 loop i need this value
// "right1"   for 6 loop i need this value
// "top1"     for 7 loop i need this value
// "bottom1"     for 8 loop i need this value

// "left2"   for 1 loop i need this value 
// "right2"  for 2 loop i need this value
}

请帮助我解决此问题。我发现很难生成字符串以及最后，左边，右边，顶部，底部的数字，并且顺序应该经过5次循环后更改数字

Answer 1

您可以使用列表项的索引和数组的长度来做到这一点。

var array = ["left", "right", "top", "bottom"];

// Dummy list array
var list = new Array(10).fill(0);

list.forEach((po, i) => {
  // based on index of list calculate position in array
  // by using remainder operator
  var j = i % array.length,
    // get repetion count by simple dividing by the length
    c = Math.floor(i / array.length);
  console.log(array[j] + c)
});

Answer 2

使用新的ECMAScript对象（例如(ns another-namespace) (defmacro def&resolve [a b] `(do (def ~a 12) (def ~b (resolve '~a)))) (macroexpand-1 '(def&resolve foo bar)) #=> (do (def foo 12) (def bar (clojure.core/resolve (quote foo)))) (def&resolve foo bar) bar #=> #'another-namespace/foo和arrow functions原型方法，以及新的fill和let变量类型，您可以这样做：< / p>

const

编辑：我使用了let instructions = ['left', 'right', 'top', 'bottom']; const ARRAY_LEN = 10; const DUMMY_ELEM = 0; let dummyArray = new Array(ARRAY_LEN).fill(DUMMY_ELEM); dummyArray.map((element, index) => { const AUX_INDEX = index % instructions.length; console.log(instructions[AUX_INDEX] + Math.floor(index / instructions.length)); })，但是您当然可以使用map，或者根据您的具体问题，甚至可以使用Array.prototype.every方法。

Answer 3

如果只需要一个值（取决于数组长度）。这可能会帮助您：

var array = ["left", "right", "top", "bottom"];
var list = [1,2,3,4,5,6,7];
var index = (list.length - 1) % array.length;
var postfix = Math.floor(list.length / array.length);
var result = array[index] + postfix;
console.log(result);

如果您需要字符串列表：

var array = ["left", "right", "top", "bottom"];
var list = [1,2,3,4,5,6,7];
var result = list.map((item, index) => array[index % array.length] + Math.floor(index / array.length));
console.log(result);

我需要创建字符串值取决于数组的长度

3 个答案: