我有一个字符串,比如Hello world我需要替换索引3处的char。如何通过指定索引替换字符?

var str = "hello world";

我需要这样的东西

str.replaceAt(0,"h");

当前回答

与vector打交道通常最有效的方法是接触String。

我建议使用以下函数:

String.prototype.replaceAt=function(index, char) {
    var a = this.split("");
    a[index] = char;
    return a.join("");
}

运行这段代码:

String.prototype.replaceAt=function(index, char) { var a = this.split(“”); a[索引] = 字符; 返回 a.join(“”); } var str = “hello world”; str = str.replaceAt(3, “#”); document.write(str);

其他回答

解决方案不工作的负索引,所以我添加了一个补丁。

String.prototype.replaceAt=function(index, character) {
    if(index>-1) return this.substr(0, index) + character + this.substr(index+character.length);
    else return this.substr(0, this.length+index) + character + this.substr(index+character.length);
    
}

我做了一个类似于你问的函数,它检查字符串中的字符是否在不允许字符数组中如果是它就用"

    var validate = function(value){
        var notAllowed = [";","_",">","<","'","%","$","&","/","|",":","=","*"];
        for(var i=0; i<value.length; i++){
            if(notAllowed.indexOf(value.charAt(i)) > -1){
               value = value.replace(value.charAt(i), "");
               value = validate(value);
            }
       }
      return value;
   }

var str = “hello world”; console.log(str); var arr = [...p]; arr[0] = “H”; p = arr.join(“”); console.log(str);

使用字符串的一行程序。替换回调(不支持表情符号):

// 0 - index to replace, 'f' - replacement string
'dog'.replace(/./g, (c, i) => i == 0? 'f': c)
// "fog"

解释道:

//String.replace will call the callback on each pattern match
//in this case - each character
'dog'.replace(/./g, function (character, index) {
   if (index == 0) //we want to replace the first character
     return 'f'
   return character //leaving other characters the same
})
"hello world".replace(/(.{3})./, "$1h")
// 'helho world'