仅当 lengh > 2 时，Javascript 才将字符串中每个单词的第一个字母大写
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Javascript capitalize first letter of each word in a string only if lengh > 2
提问by Conrado Fonseca
I looked at some questions and answers about capitalize in StackOverflow but could not find answer about my problem.
我在 StackOverflow 中查看了一些有关大写的问题和答案，但找不到有关我的问题的答案。
I would like to capitalize first letter of each word in a string only if word lengh > 2.
仅当单词 lengh > 2 时，我才想将字符串中每个单词的第一个字母大写。
My temporary solution was:
我的临时解决方案是：
var str = str.toLowerCase().replace(/\b[a-z]/g, function (letter) {
return letter.toUpperCase();
}).replace(/\b\w{1,2}\b/g, function (letter) {
return letter.toLowerCase();
});
There is a solution that can unite the two regex in one?
有没有可以将两个正则表达式合二为一的解决方案？
回答by Casimir et Hippolyte
This must do the job:
这必须完成这项工作：
str = str.toLowerCase().replace(/\b[a-z](?=[a-z]{2})/g, function(letter) {
return letter.toUpperCase(); } );
[EDIT]
[编辑]
The above example is a little naive since it assumes that there is only letters in the string, and doesn't take account that a word boundary \bcan match the limit between a word character [a-zA-Z0-9_]and a non word character or an anchor. Thus, to be more rigorous, it's better to write:
上面的例子有点幼稚，因为它假设字符串中只有字母，并且没有考虑单词边界\b可以匹配单词字符[a-zA-Z0-9_]和非单词字符或锚点之间的限制。因此，为了更严谨，最好这样写：
str = str.toLowerCase().replace(/([^a-z]|^)([a-z])(?=[a-z]{2})/g, function(_, g1, g2) {
return g1 + g2.toUpperCase(); } );
If you want to do the same but this time, including the first letter of the string (whatever the number of letters after) you can use this:
如果你想这样做，但这次，包括字符串的第一个字母（无论后面的字母数量如何），你可以使用：
str = str.toLowerCase().replace(/([^a-z])([a-z])(?=[a-z]{2})|^([a-z])/g, function(_, g1, g2, g3) {
return (typeof g1 === 'undefined') ? g3.toUpperCase() : g1 + g2.toUpperCase(); } );
回答by Matteo Tassinari
Try this:
试试这个：
var str = str.toLowerCase().replace(/\b\w{3,}/g, function (l) {
return l.charAt(0).toUpperCase() + l.slice(1);
});
回答by AntouanK
Maybe use a function to make it more clean
也许使用一个函数让它更干净
var capitalize1st = function(str){
str = str || '';
// string length must be more than 2
if(str.length<3){
return str;
}
return str[0].toUpperCase()+str.slice(1);
}
var splitWordsAndCap1st = function(str){
str = str || '';
var words = str.match(/\S+/g);
for(var i=0;i<words.length;i++){
words[i] = capitalize1st(words[i]);
}
return words.join(' ');
}
splitWordsAndCap1st("I would like to capitalize first letter of each word in a string");
回答by Hitesh Kumar
Here's a simpler solution which does the job.
这是一个更简单的解决方案，可以完成这项工作。
const capitalize = (str) =>
str.toLowerCase().replace(/\w{3,}/g, (match) =>
match.replace(/\w/, (m) => m.toUpperCase()));
回答by Xotic750
No need for regex (just one small one to capture whitespace), you could do this
不需要正则表达式（只需要一小部分来捕获空格），你可以这样做
Javascript
Javascript
function titleCaseLengthGt2(string) {
var array = string.split(/(\s+)/),
length = array.length,
i = 0,
word;
while (i < length) {
//array[i] = array[i].toLowerCase(); // make words lowercased first if you want
word = array[i];
if (word.length > 2) {
array[i] = word.charAt(0).toUpperCase() + word.slice(1);
}
i += 1;
}
return array.join("");
}
console.log(titleCaseLengthGt2("i want to be titelised"));
Output
输出
i Want to be Titelised
on jsfiddle
回答by Pierre Forestier
To capitalize first letter of each word in a string if word length > 2, I use for english text:
如果单词长度 > 2，要大写字符串中每个单词的第一个字母，我使用英文文本：
l_text = l_text.toLowerCase().replace(/(?=\b)([a-z])(?=[a-z]{2})/g,
function(g0) {return (g0.toUpperCase());});
Often in real life the rule "word length > 2" is not enough.
在现实生活中，规则“字长> 2”通常是不够的。
To capitalize town names in french I have to exclude some words like in this sample:
为了在法语中大写城镇名称，我必须排除一些像在这个示例中的单词：
l_text = "Bourg-en-Bresse, NEUILLY SUR SEINE, enghien-les-bains";
l_text = l_text.toLowerCase().replace(/(?=\b)(?!(?:d|en|les|sous|sur)\b)([a-z])/g,
function(g0) {return (g0.toUpperCase());});
For a more sophisticated situation, you may combine the negative lookahead assertion (?!(:|en|les|sous|sur)\b) and the positive lookahead assertion (?=[a-z]{2}).
对于更复杂的情况，您可以组合否定先行断言 (?!(:|en|les|sous|sur)\b) 和肯定先行断言 (?=[az]{2})。
To deal with non standard word boundary and characters out of a-z range, you may use a word boundary and characters set specific to the context:
要处理非标准词边界和 az 范围外的字符，您可以使用特定于上下文的词边界和字符集：
/(?:^|[\s'\-])(?!(?:d|en|les|sous|sur)[\s'\-])([a-zàaéèê??ù??])/g
