试图利用在字符串数组的第一个字符，这是为什么不工作？ [英] Trying to capitalize the first character in array of strings, why this is not working?

问题描述

我在JavaScript中的初学者。我试图写一个转换例如函数列表样式图片到 listStyleImage 。

我想出了一个功能，但似乎不工作。任何人都可以点我在这里的问题？

  VAR myStr中=名单样式图象功能camelize（STR）{
    变种中newstr =;
    变种newArr = [];
    如果（str.indexOf（ - ）！=  -  1）{
        newArr = str.split（ - ）;
        对于（VAR I = 1; I＆LT; newArr.length;我++）{
            newArr [I] .charAt（0）.toUpperCase（）;
        }
        中newstr = newArr.join（）;
    }
    返回中newstr;
}的console.log（camelize（myStr中））;
 

解决方案

您有实际重新分配数组元素：

 为（VAR I = 1; I＆LT; newArr.length;我++）{
        newArr [I] = newArr [I] .charAt（0）.toUpperCase（）;
    }
 

在与toUpperCase（）函数返回新的字符串，但不修改原来的。

您可能要检查，以确保 newArr [I] 是空字符串第一，如果你连续用两个破折号输入字符串。

的修改的＆MDASH;指出SO贡献者@lonesomeday正确地指出，你还需要重新粘上每个字符串的其余部分：

  newArr [I] = newArr [I] .charAt（0）.toUpperCase（）+ newArr [I] .substr（1）;
 

I'm a beginner at Javascript. I'm trying to write a function that converts for example list-style-image to listStyleImage.

I came up with a function but it seems not working. Can anybody point me to the problem here ?

var myStr = "list-style-image";

function camelize(str){
    var newStr = "";    
    var newArr = [];
    if(str.indexOf("-") != -1){
        newArr = str.split("-");
        for(var i = 1 ; i < newArr.length ; i++){
            newArr[i].charAt(0).toUpperCase();
        }       
        newStr = newArr.join("");
    }
    return newStr;
}

console.log(camelize(myStr));

解决方案

You have to actually re-assign the array element:

    for(var i = 1 ; i < newArr.length ; i++){
        newArr[i] = newArr[i].charAt(0).toUpperCase();
    }       

The "toUpperCase()" function returns the new string but does not modify the original.

You might want to check to make sure that newArr[i] is the empty string first, in case you get an input string with two consecutive dashes.

edit — noted SO contributor @lonesomeday correctly points out that you also need to glue the rest of each string back on:

         newArr[i] = newArr[i].charAt(0).toUpperCase() + newArr[i].substr(1);

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