Question

我知道您可以在${}内使用string来放置var，但此处似乎不想识别var而它不是var str = s.toLowerCase(); var counts = {}; var ch, index, len, count; for (index = 0, len = str.length; index < len; ++index) { ch = str.charAt(index); count = counts[ch]; counts[ch] = count ? count + 1 : 1; } for (ch in counts) { console.log('${ch}(${counts[ch]})'); }在括号中

{{1}}

Answer 1

ES2015 template literals需要回拨：

console.log(`${ch}(${counts[ch]})`);

工作示例：

＆＃13;

const s = 'An example string with some duplicate characters.';

var str = s.toLowerCase();
var counts = {};
var ch, index, len, count;

for (index = 0, len = str.length; index < len; ++index) {
  ch = str.charAt(index);
  count = counts[ch];
  counts[ch] = count ? count + 1 : 1;
}
for (ch in counts) {
  console.log(`${ch}(${counts[ch]})`);
}

＆＃13;

Answer 2

你需要使用后面的勾号。使用`而不是＆＃39;。

Answer 3

你需要把你的字符串放在``中，而不是＆＃39;＆＃39;。

var myVar = 'hello world!';
console.log(`${myVar}`);

字符串中的JavaScript var

3 个答案: