变量的Python字符串编码 [英] Python string encoding for a variable

问题描述

我知道对于Python<如图3所示，字符串植物大战僵尸-2的unicode编码如下：

  u植物大战僵尸。 Zombies‰？2 .encode（ utf-8）
  

如果我有一个变量该怎么办（例如appName）而不是字符串，我可以这样：

  appName = Plant vs. Zombies䋢2  
 u + appName.encode（ utf-8）
  

适用于：

  appName = appName.encode（'utf-8'）; 
 
 
'ascii'编解码器无法解码位置18的字节0xe4：序数不在范围内（128）
  

解决方案

否。 u 表示法仅适用于字符串文字。包含字符串数据的变量不需要 u ，因为该变量包含的对象可以是Unicode字符串或字节字符串。 （我在这里假设 appName 包含字符串数据；如果不包含，则尝试对其进行编码是没有意义的。将其转换为字节字符串或unicode

所以您的变量包含一个unicode字符串或一个字节字符串。如果它是unicode字符串，则可以执行 appName.encode（ utf-8）。

如果它是一个字节字符串，则已经使用某种编码进行了编码。如果已将其编码为UTF-8，则它已经是您想要的方式，您无需执行任何操作。如果它采用其他编码，并且想将其转换为UTF-8，则可以执行 appName.decode（'the-existing-encoding'）。encode（ utf-8）。

请注意，如果您执行在编辑的问题中显示的内容，则结果可能不会达到您的期望。您具有：

  appName = Plant vs. Zombies䋢2 
  

在字符串文字上没有 u 的情况下，您已经以某种编码创建了字节字符串，即源文件的编码。如果您的源文件不在UTF-8中，那么您处于我上面描述的最后一种情况。在将其创建为非unicode之后，无法仅使字符串unicode。当您将其创建为非unicode时，您是以特定的编码创建它的，并且您必须知道哪种编码才能将其解码为unicode（因此，您可以根据需要将其编码为其他编码）。 / p>

I'm aware of the fact that for Python < 3, unicode encoding for the string 'Plants vs. Zombies䋢 2' is as below:

u"Plants vs. Zombies䋢 2".encode("utf-8")

What if I have an variable (say appName) instead of a string can I do it like this:

  appName = "Plants vs. Zombies䋢 2"
 u+appName.encode("utf-8")

For:

 appName = appName.encode('utf-8');


 'ascii' codec can't decode byte 0xe4 in position 18: ordinal not in range(128)

解决方案

No. The u notation is only for string literals. Variables containing string data don't need the u, because the variable contains an object that is either a unicode string or a byte string. (I'm assuming here that appName contains string data; if it doesn't, it doesn't make sense to try to encode it. Convert it to a bytestring or unicode first.)

So your variable either contains a unicode string or a byte string. If it is a unicode string you can just do appName.encode("utf-8").

If it is a byte string then it is already encoded with some encoding. If it's already encoded as UTF-8, then it's already how you want it and you don't need to do anything. If it's in some other encoding and you want to get it into UTF-8, you can do appName.decode('the-existing-encoding').encode("utf-8").

Note that if you do what you show in your edited, question, the result might not be what you expect. You have:

appName = "Plants vs. Zombies䋢 2"

Without the u on the string literal, you have created a bytestring in some encoding, namely the encoding of your source file. If your source file isn't in UTF-8, then you're in the last situation I described above. There is no way to "just make a string unicode" after you have created it as non-unicode. When you create it as non-unicode, you are creating it in a particular encoding, and you have to know what encoding that is in order to decode it to unicode (so you can then encode it to another encoding if you want).

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