var str = "abcdffffggj";
var obj = {};
for(var i = 0; i < str.length; i++){
//charAt() 方法可返回指定位置的字符。
if(!obj[str.charAt(i)]){
obj[str.charAt(i)] = 1;
}else{
obj[str.charAt(i)]++;
}
}
console.log(obj);
var max = 0, name = "";
for(var i in obj){
if(obj[i] > max){
max = obj[i];
name = i;
}
}
console.log(name+":"+max);
var arr1 = [1,2,3];
var arr2 = [2,3,4,5,6];
let output = arr1
.filter(x => arr2.indexOf(x) == -1)
.concat(arr2.filter(x => arr1.indexOf(x) == -1));
console.log(output);
var arr = [];
for(var i = 0; i < 100; i++){
arr[i] = Math.floor(Math.random()*101);
}
console.log(arr);
var sorted = true;
for(var i = 0; i < arr.length; i++){
for(var j = 0; j < arr.length - 1 - i; j++){
if(arr[j] > arr[j+1]) {
arr[j] = [arr[j+1],arr[j+1] = arr[j]][0];
sorted=false;
}
}
if(sorted==true){
break;
}
}
function search(arr,data){
var max = arr.length-1, //最大值
min = 0; //最小值
while(min<=max){
var mid = Math.floor((max+min)/2); //中间值
if(arr[mid]<data){
min = mid+1;
}else if(arr[mid]>data){
max = mid-1;
}else{
return mid;
}
}
return -1; //没找到返回-1
}
console.log(arr);//[0, 1, 2, 2, 3, 4, 4, 4, 5, 6, 7, 10, 11, 12, 14, 15, 16, 17, 18, 18, 20, 21, 23, 24, 24, 24, 25, 25, 25, 26, 28, 28, 34, 35, 35, 38, 39, 39, 40, 40, 42, 44, 48, 48, 49, 51, 51, 51, 53, 54, 54, 54, 55, 56, 58, 59, 59, 59, 60, 61, 62, 62, 63, 63, 65, 66, 67, 68, 68, 69, 69, 71, 71, 72, 73, 74, 76, 76, 77, 82, 83, 84, 85, 86, 86, 86, 86, 87, 90, 91, 91, 94, 94, 94, 94, 95, 95, 97, 98, 100]
console.log(search(arr,25)); //27
console.log(search(arr,104)); //-1
function count(arr,data){
var count = 0;
var position = search(arr,data);
if(position>-1){
count++;
for(var i=position-1;i>0;i--){
if(arr[i]==data){
count++;
}else{
break;
}
}
for(var i=position+1;i<arr.length;i++){
if(arr[i]==data){
count++;
}else{
break;
}
}
}
return count;
}