function min(nums) {
var res = nums[0]
for (var i = 0; i < nums.length; i++) {
if (res > nums[i]) {
res = nums[i]
}
}
return res
}
function max(nums) {
var res = nums[0]
for (var i = 0; i < nums.length; i++) {
if (res < nums[i]) {
res = nums[i]
}
}
return res
}
function getMax(nums) {
return Math.max.apply(null, nums)
}
function getMin(nums) {
return Math.min.apply(null, nums)
}
var nums = [1, 12, 3, 4, 5, 0]
console.log('最大值:', max(nums))
console.log('最小值:', min(nums))
console.log('最大值:', getMax(nums))
console.log('最小值:', getMin(nums))
console.log('最大值:', Math.max(...nums))
console.log('最小值:', Math.min(...nums))
es5
var arr2 = [1, 1, 'true', 'true', true, true, 15, 15, false, false, undefined, undefined, null, null, NaN, NaN, 'NaN', 0, 0, 'a', 'a', {}, {}];
// es5常用
function unique(arr) {
for (var i = 0; i < arr.length; i++) {
for (var j = i + 1; j < arr.length; j++) {
if (arr[i] == arr[j]) { //第一个等同于第二个,splice方法删除第二个
arr.splice(j, 1);
j--; // splice会修改原数组,删了一个后,下标要减一!
}
}
}
return arr;
}
console.log(unique(arr2)) // NaN和{}没有去重,两个null直接消失了
es6
var arr2 = [1, 1, 'true', 'true', true, true, 15, 15, false, false, undefined, undefined, null, null, NaN, NaN, 'NaN', 0, 0, 'a', 'a', {}, {}];
console.log(Array.from(new Set(arr2))); // {}没有去重,两个null直接消失了
indexOf去重
var arr2 = [1, 1, 'true', 'true', true, true, 15, 15, false, false, undefined, undefined, null, null, NaN, NaN, 'NaN', 0, 0, 'a', 'a', {}, {}];
function unique1(arr) {
var newarr = [];
for (var i = 0; i < arr.length; i++) {
if (newarr.indexOf(arr[i]) == -1) {
newarr.push(arr[i])
}
}
return newarr
}
console.log(unique1(arr2)); // NaN和{}没有去重,两个null直接消失了
数组里面套对象的去重
var arr1 = [
{ name: '张三' },
{ name: '张三' },
{ name: '李四' },
{ name: '王五' },
]
function distinct1(arr, key) {
var newobj = {}, newArr = [];
for (var i = 0; i < arr.length; i++) {
var item = arr[i];
if (!newobj[item[key]]) {
newobj[item[key]] = newArr.push(item);
}
}
return newArr;
}
console.log(distinct1(arr1, 'name'));