javascript 带有转义字符的 JSON.parse
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JSON.parse with escape characters
提问by joanx737
Trying to get a handle on JSON.parse and having a difficult time understanding how escape characters are handled; specifically - why does:
试图处理 JSON.parse 并且很难理解如何处理转义字符；特别是 - 为什么：
JSON.parse('["\\\"\"a\""]')
Evaluate to:
评估为：
["\""a""]
How do the multiple backslashes work with each other?
多个反斜杠如何相互配合？
Thanks!
谢谢！
回答by Jordan Running
First of all, let's clarify what value we're actually working with:
首先，让我们澄清一下我们实际使用的值是什么：
var str = '["\\\"\"a\""]';
console.log(str);
// => ["\\"\"a\""]
As you can see, half of those backslashes had nothing to do with JSON. They were just escaping characters in the JavaScript string. The actual characters of that string are these:
如您所见，其中一半的反斜杠与 JSON 无关。它们只是转义 JavaScript 字符串中的字符。该字符串的实际字符是这些：
["\\"\"a\""]
We know that the square brackets ([]) indicate a JSON array, and the outermost quotation marks indicate a JSON string, so let's drop those:
我们知道方括号 ( []) 表示一个 JSON 数组，最外面的引号表示一个 JSON 字符串，所以让我们去掉那些：
\\"\"a\"
Now, to figure out what JavaScript string this JSON will deserialize to, let's break it up into its parts:
现在，要弄清楚此 JSON 将反序列化为哪个 JavaScript 字符串，让我们将其分解为几个部分：
\ \" \" a \"
1 2 3 4 5
I've paired up each backslash with the character that follows it (which is sometimes another backslash—backslashes are escaped with backslashes just like quotation marks are). Now for each character that's preceded by a backslash we just drop the backslash:
我将每个反斜杠与它后面的字符配对（有时是另一个反斜杠——反斜杠就像引号一样用反斜杠转义）。现在，对于前面有反斜杠的每个字符，我们只需删除反斜杠：
\ " " a "
1 2 3 4 5
Now mash it all together again:
现在再次将它们混合在一起：
\""a"
Did it work?
它起作用了吗？
var str = '["\\\"\"a\""]';
var array = JSON.parse(str);
console.log(array[0]);
// => \""a"
Yep!
是的！
P.S. Because JSON and JavaScript escaping work the same way, you could apply the same process to the original JavaScript string:
PS 因为 JSON 和 JavaScript 转义的工作方式相同，所以您可以对原始 JavaScript 字符串应用相同的过程：
["\\\"\"a\""]
Split it up again:
再次拆分：
[ " \ \ \ " \ " a \ " " ]
1 2 3 4 5 6 7 8 9 10 11 12 13
You'll notice that in this case only backslashes are escaped—that's because in our JavaScript the string was surrounded by single-quotes, so the double-quotes didn't have to be escaped. Now, drop the initial backslashes again and we get:
你会注意到，在这种情况下，只有反斜杠被转义——这是因为在我们的 JavaScript 中，字符串被单引号包围，所以双引号不必被转义。现在，再次删除初始反斜杠，我们得到：
[ " \ \ \ " \ " a \ " " ]
1 2 3 4 5 6 7 8 9 10 11 12 13
And squash it together again:
然后再次将其压扁：
["\\"\"a\""]
You'll recognize this as the original value we started with.
您会认识到这是我们开始时的原始值。
回答by Spencer Wieczorek
In this case JavaScript escaping actually works in steps. Basically meaning the string is escaped initially, but then the result after that is then escaped again. So the first escape acts like so:
在这种情况下，JavaScript 转义实际上是分步进行的。基本上意味着字符串最初被转义，但之后的结果再次被转义。所以第一个逃生行为是这样的：
Step 1:
["\\\\\\"\\"a\\""]==>["(\\)(\\)(\\)"\(\")a\(\")"]==>["\\\"\"a\""]
第 1 步：
["\\\\\\"\\"a\\""]==>["(\\)(\\)(\\)"\(\")a\(\")"]==>["\\\"\"a\""]
In this first step each \\converts to a \and \"to a ". A better look at which items are being converted (I've added (..)around the converted items in this step, where (\\)converts to \and (\")converts to ").
在第一步中，每个都\\转换为 a\和\"a "。更好地了解正在转换的项目（我(..)在此步骤中添加了已转换的项目，其中(\\)convert to\和(\")converts to "）。
Step2:
["\\\"\"a\""]==>["(\\)(\")(\")a(\")"]==>["\""a""]
第二步：
["\\\"\"a\""]==>["(\\)(\")(\")a(\")"]==>["\""a""]
回答by Nazir Ullah
the same problem with me but i solve with this sample code.
我也有同样的问题，但我用这个示例代码解决了。
def escape(str):
str = str.replace('\', '\\').replace('"', '\"').replace('\n', '\n').
replace('\t', '\t')
result = []
for ch in str:
n = ord(ch)
if n < 32:
h = hex(n).replace('0x', '')
result += ['\u%s%s' % ('0'*(4-len(h)), h)]
else:
result += [ch]
return ''.join(result)
