将toLowerCase的操作限制为字符串的一部分？

Question

我想将大多数字符串转换为小写,除了括号内的那些字符.将括号外的所有内容转换为小写后,我想删除括号.所以给出{H}ell{o} World输入应该Hello world作为输出.删除括号很简单,但是有没有办法用正则表达式选择性地使括号小写之外的所有内容？如果没有简单的正则表达式解决方案,那么在javascript中最简单的方法是什么？

Answer 1

你可以试试这个：

var str='{H}ell{o} World';

str = str.replace(/{([^}]*)}|[^{]+/g, function (m,p1) {
    return (p1)? p1 : m.toLowerCase();} );

console.log(str);

模式匹配：

{([^}]*)}  # all that is between curly brackets
           # and put the content in the capture group 1

|          # OR

[^{]+      # anything until the regex engine meet a {
           # since the character class is all characters but {

回调函数有两个参数：

m完整的比赛

p1第一个捕获组

p1如果不为空，则返回p1整个匹配m小写。

细节：

"{H}"    p1 contains H (first part of the alternation)
         p1 is return as it. Note that since the curly brackets are
         not captured, they are not in the result. -->"H"

"ell"    (second part of the alternation) p1 is empty, the full match 
         is returned in lowercase -->"ell"

"{o}"    (first part) -->"o"

" World" (second part) -->" world"