随机打乱一个数组
思路:从数组的最后一项开始,随机选择前面的一个元素进行交换,然后一步步往前交换
//思路1:
var shuffle = arr =>{
let end = arr.length-1;
while(end){
const index = Math.floor(Math.rendom() * (end+1));
[arr[index], arr[end]] = [arr[end], arr[index]];
end = end-1;
}
return arr;
}
//思路2:
var arr2 = [1,2,3,4,5,6,7]
function Ran(a,b){
return Math.random() >=0.5 ? 1 :-1
}
arr2.sort(Ran)
console.log(arr2)
求数组元素min和max值
function findMin(num){
var a = num[0];
for(var i =0;i<num.length;i++){
if(a > num[i]){
a = num[i]
}
}
return a
}
function findMax(num){
var a = num[0];
for(var i =0;i<num.length;i++){
if(a < num[i]){
a = num[i]
}
}
return a
}