当一个字符串被传递给一个带有返回语句的函数时,你如何在JavaScript中反转它,而不使用内置函数(.reverse(), . charat()等)?
当前回答
function reverseString(string) {
var reversedString = "";
var stringLength = string.length - 1;
for (var i = stringLength; i >= 0; i--) {
reversedString += string[i];
}
return reversedString;
}
其他回答
你可以尝试这样做。我相信还有重构的空间。我无法使用分裂函数。也许有人知道不分裂的方法。
代码设置,可以把它放在你的。js库
使用它的代码(有客户端代码,只是因为它在浏览器中测试过):
var sentence = "My Stack is Overflowing."
document.write(sentence.reverseLetters() + '<br />');
document.write(sentence.reverseWords() + '<br />');
代码片段:
String.prototype.aggregate = function(vals, aggregateFunction) { var temp = ''; for (var i = vals.length - 1; i >= 0; i--) { temp = aggregateFunction(vals[i], temp); } return temp; } String.prototype.reverseLetters = function() { return this.aggregate(this.split(''), function(current, word) { return word + current; }) } String.prototype.reverseWords = function() { return this.aggregate(this.split(' '), function(current, word) { return word + ' ' + current; }) } var sentence = "My Stack is Overflowing." document.write(sentence.reverseLetters() + '<br />'); document.write(sentence.reverseWords() + '<br />');
function reverseString(string) {
var reversedString = "";
var stringLength = string.length - 1;
for (var i = stringLength; i >= 0; i--) {
reversedString += string[i];
}
return reversedString;
}
没有将字符串转换为数组;
String.prototype.reverse = function() {
var ret = "";
var size = 0;
for (var i = this.length - 1; -1 < i; i -= size) {
if (
'\uD800' <= this[i - 1] && this[i - 1] <= '\uDBFF' &&
'\uDC00' <= this[i] && this[i] <= '\uDFFF'
) {
size = 2;
ret += this[i - 1] + this[i];
} else {
size = 1;
ret += this[i];
}
}
return ret;
}
console.log('anãnam anañam' === 'mañana mañana'.reverse());
使用数组。反向而不将字符转换为代码点;
String.prototype.reverse = function() {
var array = this.split("").reverse();
for (var i = 0; i < this.length; ++i) {
if (
'\uD800' <= this[i - 1] && this[i - 1] <= '\uDBFF' &&
'\uDC00' <= this[i] && this[i] <= '\uDFFF'
) {
array[i - 1] = array[i - 1] + array[i];
array[i] = array[i - 1].substr(0, 1);
array[i - 1] = array[i - 1].substr(1, 1);
}
}
return array.join("");
}
console.log('anãnam anañam' === 'mañana mañana'.reverse());
以下是可以用来实现字符串反转的四种最常用方法
给定一个字符串,返回一个新字符串 字符顺序
问题的多种解决方案
//reverse('apple') === 'leppa'
//reverse('hello') === 'olleh'
//reverse('Greetings!') === '!sgniteerG'
// 1. First method without using reverse function and negative for loop
function reverseFirst(str) {
if(str !== '' || str !==undefined || str !== null) {
const reversedStr = [];
for(var i=str.length; i>-1; i--) {
reversedStr.push(str[i]);
}
return reversedStr.join("").toString();
}
}
// 2. Second method using the reverse function
function reverseSecond(str) {
return str.split('').reverse().join('');
}
// 3. Third method using the positive for loop
function reverseThird(str){
const reversedStr = [];
for(i=0; i<str.length;i++) {
reversedStr.push(str[str.length-1-i])
}
return reversedStr.join('').toString();
}
// 4. using the modified for loop ES6
function reverseForth(str) {
const reversedStr = [];
for(let character of str) {
reversedStr = character + reversedStr;
}
return reversedStr;
}
// 5. Using Reduce function
function reverse(str) {
return str.split('').reduce((reversed, character) => {
return character + reversed;
}, '');
}
保持干燥和简单,傻!!
function reverse(s){
let str = s;
var reverse = '';
for (var i=str.length;i>0;i--){
var newstr = str.substring(0,i)
reverse += newstr.substr(-1,1)
}
return reverse;
}