Question

我的要求不仅是大写字符串的首字符，还有一个段落，而且我想像移动设备键盘一样大写每个字符串的首字符。

我尝试了以下解决方案，但不能满足我的要求：

$('#test').blur(function(event) {
 var value = $(this).val();

 var output = "";

 output = value.charAt(0).toUpperCase() + value.slice(1);

});

以上代码仅将首字母大写。

示例输入：

l orem ipsum只是印刷和排版行业的伪文本。自1500年代以来， l orem ipsum一直是业界标准的伪文本，当时一位不知名的打印机拿起一个厨房，将其打乱成一本标本。 t 它！

预期输出：

L orem Ipsum只是印刷和排版行业的伪文本。自1500年代以来， L orem Ipsum一直是行业标准的伪文本，当时一位不知名的打印机拿起一个厨房，将其打乱成一本标本。 T 它！

Answer 1

您可以使用正则表达式：匹配字符串的开头或句点，后跟空格，然后匹配字母字符，然后使用替换函数在该字符上调用toUpperCase。要正确替换?和!以及.之后的字母，请使用字符集[.?!]：

const input = `lorem ipsum is simply dummy text of the printing and typesetting industry. lorem ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.that's it!`;
const cleaned = input.replace(
  /(^|\[.?!] *)([a-z])/g,
  (_, g1, g2) => g1 + g2.toUpperCase()
);
console.log(cleaned);

要不替换省略号，可以在第一组的.之前再匹配一个字符：

const input = `foo bar. bar baz... baz buzz? buzz foo`;
const cleaned = input.replace(
  /(^|(?:[?!]|[^.]\.) *)([a-z])/g,
  (_, g1, g2) => g1 + g2.toUpperCase()
);
console.log(cleaned);

图案

(^|(?:[?!]|[^.]\.) *)([a-z])

表示：

(^|(?:[?!]|[^.]\.) *)-在第一组中捕获：
- ^-字符串的开头，或者：
- (?:[?!]|[^.]\.)-匹配上一个句子的结尾：
  - [?!]-问号或感叹号，或者
  - [^.]\.-非句号，后跟句号
- *后跟任意数量的空格字符
([a-z])-在第二组中捕获任何字母字符

然后

  (_, g1, g2) => g1 + g2.toUpperCase()

替换为第一组，将第二组替换为小写。

Answer 2

尝试

<script>
      var input = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.That's it!";

      console.log( input.charAt(0).toUpperCase() + input.slice(1))

</script>

Answer 3

您可以将String#replace()方法与以下正则表达式匹配：

/\.\s*\w/

与自定义replace回调结合使用，该回调将匹配的字符串大写以实现此目的。这里的基本思想是将紧跟句号（即\.）后第一个字母的所有子字符串大写。正则表达式还考虑了在句号和下一个字母字符（即\s*）之间出现零个或多个空格（即\w）的情况：

var input = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.That's it!";

var result = input.replace(/\.\s*\w/, function(match) {
  return match.toUpperCase();
});

console.log('Regular expression based approach', result);

此外，我在评论中注意到您询问了不需要正则表达式的方法。尽管通常会从此类问题中首选使用正则表达式，但以下内容显示了一种非基于re的方法：

const input = `lorem ipsum is simply dummy text of the printing and typesetting industry. lorem ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.that's it!`;

console.log('Non regular expression based approach:',

input
.split('.')
.map((sentence) => {

  for (var i = 0; i < sentence.length; i++) {

    if (sentence[i] !== ' ') {
    
      sentence = sentence.substr(0, i) + sentence[i].toUpperCase() + sentence.substr(i + 1);      
      break;
    }
  }

  return sentence
})
.join('.')
)

Answer 4

假设您的原始输入不包含任何..，那么下面是一个可行的解决方案：

const raw = `lorem ipsum is simply dummy text of the printing and typesetting industry. lorem ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.that's it!`

const formatted =
  raw
    .split('.')
    .map(sentence => sentence.trim())
    .map(sentence => sentence.charAt(0).toUpperCase() + sentence.slice(1))
    .join('. ')

console.log(formatted)
// Lorem ipsum is simply dummy text of the printing and typesetting industry. Lorem ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. That's it!

Answer 5

let paragraph = document.querySelector('#test').textContent;

let result = paragraph.split('.')
    .map(sentence => sentence.trim())
    .map(sentence => {
        sentence = sentence.replace(sentence[0], sentence[0].toUpperCase()) + sentence.slice(1);
        return sentence;
    });


console.log(result.join('. '));

如何在大写之后大写字符串的所有字符。像手机键盘一样

5 个答案: