javascript - 如何更改该字符串中的字母形式？

Question

我想让字符串“hello”变为“hElLo”，它只是索引中的偶数更改为大写字母。

源代码:

function toWeirdCase(s){
 var str = s.split(''); // var str = {'h','e','l','l','o'}
 for(var i = 0; i<str.length; i++){
    if(str.length[i]%2===0){
        return str.toUpperCase();
    }
   }
  }

console.log(toWeirdCase('hello'))

但结果是未定义

Answer 1

你可以这样做:

function toWeirdCase(s) {
  var str = s.split(''); // var str = {'h','e','l','l','o'}
  for (var i = 0; i < str.length; i++) {
    if (i % 2 !== 0) {                      //Test the index and not the letter
                                            //Since the goal is to capitalized the odd numbers (array starts at 0). You can use the condition i % 2 !== 0. This means the index reminder is not 0.
      str[i] = str[i].toUpperCase();        //Assign the value
    }
  }

  return str.join('');                      //Join the array and return
}

console.log(toWeirdCase('hello'))