一个字符串里出现最多的字符是什么，以及出现次数

[sisterAn]

[ohion]

function mostCharInStr(str){
 let obj = {}
 let arr = str.split('');
 let max = 1;
 let s = arr[0]
 for(let i=1;i<arr.length;i++){
 if(obj[arr[i]]){
 let count = ++obj[arr[i]]
 if(count > max){
 max = count
 s = arr[i]
 }
 }else{
 obj[arr[i]] = 1
 }
 }
 return [s,max]
}

[sisterAn]

再补充一种：使用正则

const mostCharInStr = (str) => {
 let temp = str.split('').sort().join('')
 // 先进行排序处理，然后重新组装成字符串
 let reg = /(\w)\1+/g
 let num = 0
 let value = null
 temp.replace(reg, function($0, $1){
 if (num < $0.length) {
 num = $0.length
 value = $1
 };
 });
 return {num, value}
}

// 测试
let str = 'dsfshkgfareasfd'
console.log(mostCharInStr(str))
// {num: 3, value: "f"}

[mingju0421]

let str = 'Once you learn to quit, it becomes a habit.'
const 出现最多的字符以及次数 = str => {
 let 记录出现次数最多的字符 = str[0], 字符映射 = {}
 for (let s of str) {
 if (s == ' ') continue
 s = s.toLowerCase()
 字符映射[s] = 字符映射[s] ? 字符映射[s] + 1 : 1
 记录出现次数最多的字符 = 字符映射[记录出现次数最多的字符] > 字符映射[s] ? 记录出现次数最多的字符 : s
 }
 return [记录出现次数最多的字符, 字符映射[记录出现次数最多的字符]]
}
console.log(出现最多的字符以及次数(str))

[cutie6]

再补充一种：使用正则

const mostCharInStr = (str) => {
 let temp = str.split('').sort().join('')
 // 先进行排序处理，然后重新组装成字符串
 let reg = /(\w)\1+/g
 let num = 0
 let value = null
 temp.replace(reg, function($0, $1){
 if (num < $0.length) {
 num = $0.length
 value = $1
 };
 });
 return {num, value}
}

// 测试
let str = 'dsfshkgfareasfd'
console.log(mostCharInStr(str))
// {num: 3, value: "f"}

需要对正则的数字引用非常熟悉才能想到这种解法吧

[laiyingzeng]

function mostCharInStr(str){
 let obj = {}
 let arr = str.split('');
 let max = 1;
 let s = arr[0]
 for(let i=1;i<arr.length;i++){
 if(obj[arr[i]]){
 let count = ++obj[arr[i]]
 if(count > max){
 max = count
 s = arr[i]
 }
 }else{
 obj[arr[i]] = 1
 }
 }
 return [s,max]
}

for 循环 i 应该从 0 开始

[NoBey]

function mostCharInStr(str){
 return ((obj, k = Object.keys(obj).sort((a, b) => obj[b] - obj[a])[0]) => [k, obj[k]]
 )(str
 .split('')
 .reduce((obj, k) => ({...obj, [k]: (obj[k]||0)+1 }), 
 {})
 ) 
}

[AlexZhang11]

function getMostChar(str){
 let i = 0
 let obj = {}
 while(i<str.length){
 let c = str.charAt(i)
 if(obj.hasOwnProperty(c)){
 obj[c]+=1
 }else{
 obj[c]=1
 }
 i++
 }
 let maxValue = 0
 let res = {}
 for(let key in obj){
 if(obj[key]>maxValue){
 res={}
 maxValue = obj[key]
 res[key] = obj[key]
 }else{
 if(obj[key]==maxValue){
 res[key] = obj[key]
 }
 }
 }
 return res
}

console.log(getMostChar('aaansbsdddksda'))