1、要求将数组中的0项去掉,将不为0的值存入一个新的数组,生成新的数组
方法一 filter
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
console.log(arr.filter((val) => val !== 0))
方法二
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
var newArr = []
arr.forEach((val, index, array) => {
if (val !== 0) newArr.push(val);
});
console.log(newArr)
2、数组[4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0]去重
方法一 indexOf
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
var newArr = []
arr.forEach(val => {
// var have = newArr.indexOf(val)
// if (have === -1) newArr.push(val);
newArr.indexOf(val) === -1 ? newArr.push(val) : newArr;
});
console.log(newArr)
方法二 includes
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
var newArr = []
arr.forEach(val => {
newArr.includes(val) || newArr.push(val);
//newArr.includes(val) ? newArr : newArr.push(val);
});
console.log(newArr)
方法三 sort
var arr = [4, 0, 7, 9, 0, 0];
arr.sort((a, b) => a - b)
var newArr = [];
arr.forEach((val, index) => {
val !== arr[index + 1] && newArr.push(val)
});
console.log(newArr)
方法四 set方法
推荐 快 简洁
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
console.log(Array.from(new Set(arr)))
方法五 for...of + Object
推荐 超快
var arr = [4, 0, 7, 9, 0, 0, 2, 6, 0, 3, 1, 0];
var obj = {};
var newArr = [];
for (var i of arr) {
if (!obj[i]) {
newArr.push(i)
obj[i] = 1;
}
}
console.log(newArr)