var str = "abcd"; console.log(str[___]) 预期输出结果: b
时间: 2024-04-18 17:23:49 浏览: 12
根据给出的代码,预期输出结果是 "b"。
在代码,`str` 是一个字符串变量我们想要访问字符串中的某个字符。在 JavaScript 中,我们可以使用方括号操作符 `[]` 来访问字符串中特定位置的字符。字符串的索引从 0 开始,所以第一个字符的索引是 0,第二个字符的索引是 1,依此类推。
根据预期输出结果是 "b",我们可以知道要访问的字符是字符串中的第二个字符。所以正确的代码应该是:
```javascript
var str = "abcd";
console.log(str[1]);
```
运行代码后,输出结果就是 "b"。
相关问题
20.【填空题】 (共2分) 要想以下JavaScript代码符合预期,空格处应该填什么? var str = "abcd"._("a", "b") console.log(str)预期输出结果: bbcd
要想以下JavaScript代码符合预期,空格处应该填写 "replace"。
正确的代码如下所示:
var str = "abcd".replace("a", "b");
console.log(str);
这段代码的意思是,使用字符串的 replace() 函数将第一个出现的字符 "a" 替换为 "b"。在这个例子中,字符串 "abcd" 中的第一个字符是 "a",所以被替换为 "b",得到的结果是 "bbcd"。最后通过 console.log() 函数输出变量 str 的值,预期的输出结果是 "bbcd"。
;JavaScriptThis time no story, no theory. The examples below show you how to write function accum: Examples: accum("abcd") -> "A-Bb-Ccc-Dddd" accum("RqaEzty") -> "R-Qq-Aaa-Eeee-Zzzzz-Tttttt-Yyyyyyy" accum("cwAt") -> "C-Ww-Aaa-Tttt"
Sure! Here's an example of how you can write the `accum` function in JavaScript:
```javascript
function accum(str) {
// Convert the string to lowercase
str = str.toLowerCase();
// Create an empty array to store the result
var result = [];
// Iterate over each character in the string
for (var i = 0; i < str.length; i++) {
// Create a string with the current character repeated i+1 times
var repeat = str[i].repeat(i + 1);
// Capitalize the first character of the repeated string
repeat = repeat.charAt(0).toUpperCase() + repeat.slice(1);
// Push the repeated and capitalized string to the result array
result.push(repeat);
}
// Join the elements of the result array with hyphens
return result.join("-");
}
console.log(accum("abcd")); // Output: "A-Bb-Ccc-Dddd"
console.log(accum("RqaEzty")); // Output: "R-Qq-Aaa-Eeee-Zzzzz-Tttttt-Yyyyyyy"
console.log(accum("cwAt")); // Output: "C-Ww-Aaa-Tttt"
```
The `accum` function takes a string as input and returns a modified string where each character is repeated a number of times based on its position in the string. The first occurrence of the character is capitalized, and all repetitions are separated by hyphens.