[js] 第72天 写一个字符串重复的repeat函数

[haizhilin]

第72天 写一个字符串重复的repeat函数

[九旬]

var str='abcd';
function repeat(str,n){
    var type = typeof(str) === 'string';
    var result='';
    if(!type){
        return 'Type Error';
    }
    for(var i=0;i<n;i++){
        result += str;
    }
    return result;
}
repeat(str,2);//'abcdabcd'

[haizhilin]

@AnsonZnl 不错，还有别的方法吗？

[九旬]

@AnsonZnl 不错，还有别的方法吗？

var str='abcd';
function repeat(str,n){
    if((typeof str) === 'string'){
       return (new Array(n+1)).join(str)
    }
    return 'Type Error'
 }
 repeat(str,3)//abcdabcdabcd

百度看到的哈哈

[haizhilin]

@AnsonZnl 也不错，还有别的方法吗？

[Andy]

const repeat = (str, n)=>str.repeat(n)

[Andy]

const repeat = (str,n)=>str.padEnd(((n+1)*str.length,str)

[毛球]

const repeatStr = (str, num) => {
  return Array(num + 1).fill(str).join('')
}

[Hortense Kovacek]

const repeat = (str) => {return typeof(str) === 'string' ?str+str:'type error';}

[Konata9]

const repeatStr = ({str = "", repeat = 1}) => {
  if (!str || repeat === 0) {
    return str;
  }

  return (str += repeatStr({str: str, repeat: (repeat -= 1)}));
};

console.log(repeatStr({str: "abc", repeat: 3}));
console.log(repeatStr({str: "abc_e", repeat: 2}));
console.log(repeatStr({str: "abc||", repeat: 4}));
console.log(repeatStr({str: "a b c_", repeat: 2}));
console.log(repeatStr({str: "_abc_", repeat: 3}));
console.log(repeatStr({str: "_abc_"}));

[Yuexun]

时间复杂度：O(logN)

const repeat = (str, count) => {
  if (count === 0) {
    return '';
  }
  if (count === 1) {
    return str;
  }

  let result = repeat(str + str, count >> 1)
  if (count & 1) {
    result += str;
  }
  return result;
}

[Alonggg]

let a = [...b , ...c].join() b或者c给一个空数组 菜鸡前端 方法有点偏门 不知道对不对

[tree]

const repeat = function (str, count,sumStr='') {
    if(typeof str !=='string'){
        return 'type error';
    }
    sumStr = sumStr + str;
    return count !==1 ? repeat(str,--count,sumStr):sumStr;
}

[VijayAdam]

String.prototype.repeat = function (count) {
  let originStr = String(this);
  let thisStr = this;
  for (let i = 1; i < count; i++) {
    thisStr += originStr;
  }
  return thisStr
};
console.log("asd".repeat(2));

[woodPeckerAnos]

ES6本身提供了String实例的repeat方法，如果还要手写，一般是考虑兼容性问题，得用旧的语法

function repeat (str, times) {
    if (typeof String.prototype.repeat === 'function') {
      return str.repeat(times)
    } else {
      var arr = new Array(times)
      for (var i = 0; i < times; i++) {
        arr[i] = str
      }
      return arr.join('')
    }
  }

[seho]

var str = "123";
var number = 4;

console.log(test4());

function test1() {
return str.repeat(number);
}

function test2() {
return new Array(number + 1).join(str);
}

function test3() {
let result = "";
for (let i = 0; i < number; i++) {
result += str;
}
return result;
}

function test4() {
let arr = new Array(number);
for (let key in arr) {
arr[key] = str;
}
return arr.join("");
}

[zhangkuibao]

function repeat(str,n) {
var result = '';
while(n-- > 0){
result += str;
}
return result ;
}

[MrZ]

@AnsonZnl 不错，还有别的方法吗？

var str='abcd';
function repeat(str,n){
    if((typeof str) === 'string'){
       return (new Array(n+1)).join(str)
    }
    return 'Type Error'
 }
 repeat(str,3)//abcdabcdabcd

百度看到的哈哈

[drunk喵咪]

String.prototype.myRepeat = function(){
    const num = arguments[0]
    const str = this.toString()
    if(typeof num !== 'number'){
        throw new Error('参数要为number类型')
    }
    let result = ''
    if(num === 0){
        result = ''
    } else if( num > 0 && num !== Infinity  ){
        for(let i = 0;i < num ; i++){
            result += str
        }
    } else {
        throw new Error('请输入正确的参数')
    }
    return result
}
const str = 'repeat'
let newStr = str.myRepeat(5)
console.log(newStr)

[xiaoqiangz]

function repeat(str, num) {
if (typeof num !="number") {
throw new Error('必须为number类型')
}
let result = ''
if (num > 0 && num < Infinity) {
// for(let i=0; i < num; i++) {
// result += str
// }
result = new Array(num).join(str)
}
return result
}

• console.log(repeat('res26', 5))