检查字符串是否是 JavaScript 中的回文
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Check if a String is a Palindrome in JavaScript
提问by Austin Hansen
The requirements for this task are that the code is returns a 'true' or 'false' for an input string. The string can be a simply word or a phrase. The other question does not address these needs. Please reopen and answer here. I am working on a function to check if a given string is a palindrome. My code seems to work for simple one-word palindromes but not for palindromes that feature capitalization or spaces.
此任务的要求是代码为输入字符串返回“真”或“假”。字符串可以是简单的单词或短语。另一个问题没有解决这些需求。请重新打开并在此处回答。我正在研究一个函数来检查给定的字符串是否是回文。我的代码似乎适用于简单的单字回文，但不适用于具有大写或空格的回文。
function palindrome(str)
{
var palin = str.split("").reverse().join("");
if (palin === str){
return true;
} else {
return false;
}
}
palindrome("eye");//Succeeds
palindrome("Race car");//Fails
回答by Walter Chapilliquen - wZVanG
First the string is converted to lowercase. Also, the characters that are not the alphabet are removed. So the string comparison becomes a array, then invert it, and convert it to string again.
首先将字符串转换为小写。此外，删除不是字母表的字符。所以字符串比较变成了一个数组，然后将它取反，再转换成字符串。
Step 1: str1.toLowerCase().replace(...) => "Race car" => "race car" => "racecar"
Step 2: str2.split("") => ["r","a","c","e","c","a","r"] => .reverse().join() => "racecar"
Result: str1 === str2
function palindrome(str) {
str = str.toLowerCase().replace(/[^a-z]+/g,"");
return str === str.split("").reverse().join("")
}
alert(palindrome("eye")); //true
alert(palindrome("Race car")); //true
alert(palindrome("Madam, I'm Adam")); //true回答by KooiInc
Something like if (word === word.split('').reverse().join('')) {/*its a palindrome!*/}I'd say
就像if (word === word.split('').reverse().join('')) {/*its a palindrome!*/}我会说的
An isPalindromeString extention:
一个isPalindrome字符串extention：
String.prototype.isPalindrome = function () {
var cleaned = this.toLowerCase().match(/[a-z]/gi).reverse();
return cleaned.join('') === cleaned.reverse().join('');
}
var result = document.querySelector('#result');
result.textContent = "'eye'.isPalindrome() => " + 'eye'.isPalindrome() +
"\n'Something'.isPalindrome() => " + 'Something'.isPalindrome() +
"\n'Race Car'.isPalindrome() => " + 'Race Car'.isPalindrome() +
"\n'Are we not drawn onward, we few, drawn onward to new era?'.isPalindrome() => " +
'Are we not drawn onward, we few, drawn onward to new era?'.isPalindrome() +
"\n'Never even or odd'.isPalindrome() => " + 'Never even or odd'.isPalindrome() +
"\n'Never odd or even'.isPalindrome() => " + 'Never odd or even'.isPalindrome();
;<pre id="result"></pre>回答by Adam Morsi
function palindrome(str) {
let letters = str.split('').filter(function (str) {
return /\S/.test(str);
});
let reversedLetters = str.split('').reverse().filter(function (str) {
return /\S/.test(str);
});
for (let i = 0; i < letters.length; i++) {
if (letters[i].toLowerCase() !== reversedLetters[i].toLowerCase()) {
return false;
}
}
return true;
}
console.log(palindrome("eye")); //true
console.log(palindrome('Race car')); //true
回答by stefan
const palindromes = arrayOfWords.filter((item) => {
return item === item.split('').reverse().join('');
})
This is an example :-)
这是一个例子:-)
回答by Vahid Akhtar
Palindrome using ES6
使用 ES6 的回文
const checkPalindrome=(str)=> {
return str.toLowerCase().trim() === str.toLowerCase().trim().split('').reverse().join('');
}
console.log(checkPalindrome("Level "))回答by Arslan Mujeeb
function palindrome(str) {
var st='';
st=str.replace(/[^a-z0-9]/ig,"").toLowerCase();
var arr=[];
arr=st.split('');
arr=arr.reverse();
var strr='';
strr=arr.join('');
if(strr==st) {
return true;
}
return false;
}
palindrome("A man, a plan, a canal. Panama");//calling the function
回答by Yakir Fitousi
//1. change the string to an array //2. use the reverse method //3. return the array as a string //4. return input= new reversed string
//1. 将字符串更改为数组 //2。使用反向方法//3。将数组作为字符串返回 //4。返回输入=新的反转字符串
var lowerCasedString = inputString.toLowerCase();
var reversedString = lowerCasedString.split("").reverse().join("");
return reversedString === lowerCasedString;hope this would be helpful:
}
var lowerCasedString = inputString.toLowerCase();
var reversedString = lowerCasedString.split("").reverse().join("");
return reversedString === lowerCasedString;希望这会有所帮助：
}
