反斜杠 - 正则表达式 - Javascript
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Backslashes - Regular Expression - Javascript
提问by Leo Selig
I wanted to build a JS function concatting a list of arguments to a valid path (since I could not be sure whether a part of the path is given with or without slashes)
我想构建一个 JS 函数，将参数列表连接到有效路径（因为我无法确定路径的一部分是否带有斜杠）
This is the function:
这是函数：
concatPath = function() {
var path = "";
for(var i = 0; i < arguments.length; i++) {
path += arguments[i].replace("(\|/)$|^(\|/)", "") + "/";
}
return path;
}
The used RegEx matched all beginning and ending slashes and backslashes on http://regexpal.comBut the function does not work properly (RegEx does not match). Furthermore, Chrome states
使用的正则表达式匹配了http://regexpal.com上的所有开始和结束斜杠和反斜杠， 但该功能无法正常工作（正则表达式不匹配）。此外，Chrome 声明
SyntaxError: Invalid regular expression: /()$|^()/: Unterminated group
语法错误：无效的正则表达式：/()$|^()/：未终止的组
when I just use the RegEx
当我只使用 RegEx
(\)$|^(\)
However, using the RegEx
但是，使用正则表达式
(\)$|^(\)
works fine.
工作正常。
Is it too late or did I missed something special?
是不是太晚了，还是我错过了一些特别的东西？
Thanks in advance!
提前致谢！
Leo
狮子座
回答by Mark Reed
You should use a regular expression literal (/.../) instead of a string literal ('...'or "...") in the call to replace. Strings have their own interpretation of backslashes that kicks in before the regular expression constructor gets a crack at it, so you need an extra level of quoting.
您应该使用正则表达式文本（/.../），而不是一个字符串（'...'或"..."在调用）replace。字符串对反斜杠有自己的解释，在正则表达式构造函数破解之前就开始使用，因此您需要额外的引用级别。
Match one backslash, regular expression literal: /\\/
匹配一个反斜杠，正则表达式字面量： /\\/
Match one backslash, regular expression in a string: '\\\\'
匹配一个反斜杠，字符串中的正则表达式： '\\\\'
But in a regex literal, you also have to put backslashes in front of the forward slashes, since forward slashes are the delimiter for the whole thing:
但是在正则表达式文字中，您还必须在正斜杠前面放置反斜杠，因为正斜杠是整个事物的分隔符：
path += arguments[i].replace(/(\|\/)$|^(\|\/)/, "") + "/";
Or, if you're married to the use of strings for some reason, this should also work:
或者，如果您出于某种原因与使用字符串结婚，这也应该有效：
path += arguments[i].replace("(\\|/)$|^(\\|/)", "") + "/";
As a side note, when your alternatives are single characters, (x|y)is overkillish; you can just use character classes: [xy]. In which case you get this:
附带说明一下，当您的替代品是单个字符时，(x|y)就太过分了；你可以只使用字符类：[xy]. 在这种情况下，你会得到这个：
path += arguments[i].replace(/[\\/]$|^[\\/]/, "") + "/";
path += arguments[i].replace("[\\/]$|^[\\/]", "") + "/";
回答by agent-j
Try this... it's a little easier to follow with the [character classes]. to match a single \with a javascript string you need \\\\, which may be what's going on.
试试这个……使用 [字符类] 会更容易一些。将单个\与您需要的 javascript 字符串匹配\\\\，这可能是正在发生的事情。
new Regexp('^[\\\\/]|[\\\\/]$')
new Regexp('^[\\\\/]|[\\\\/]$')
You can also try the /^[\\\/]|[\\\/]$/gnotation.
您也可以尝试/^[\\\/]|[\\\/]$/g符号。
s = 'c:\folder\'
console.log(s.replace(/^[\\/]|[\\/]$/g, ''))
