blocks|key|332562|text|我认为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|332563|from+io+import+open|code-block|syntax|javascript|332564|应该可以。|332565|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I think 

<pre><code>from io import open
</code></pre>

should do.

blocks|key|549147|text|1.在Python+2中获取编码参数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|549148|如果你只需要支持Python2.6和2.7，你可以用io.open代替open。io是Python3的新io子系统，它也存在于Python2、6和2.7中。请注意，在Python2.6(以及3.0)中，它完全是用Python实现的，而且速度非常慢，所以如果你需要读取文件的速度，这不是一个好的选择。|offset|length|style|CODE|549149|如果您需要速度，并且需要支持Python2.6或更早版本，则可以使用codecs.open。它还有一个编码参数，除了处理行尾的方式不同之外，它与io.open非常相似。|549150|2.要获得一个Python3+open()风格的文件处理程序，它可以流式传输字节串：|549151|open(filename,+'rb')|code-block|syntax|javascript|549152|注意“b”，意思是“二进制”。|549153|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/2/library/io.html#io.open|1|https://docs.python.org/2/library/codecs.html#codecs.open^0|0|Q|7|Z|4|14|2|Q|7|0|0|Y|B|20|7|Y|B|1|0|F|6|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@$D|14|E|15|F|G]|$D|16|E|17|F|G]|$D|18|E|19|F|G]]|9|@$D|1A|E|1B|1|1C]]|A|$]]|$1|H|3|I|5|6|7|1D|8|@$D|1E|E|1F|F|G]|$D|1G|E|1H|F|G]]|9|@$D|1I|E|1J|1|1K]]|A|$]]|$1|J|3|K|5|6|7|1L|8|@$D|1M|E|1N|F|G]]|9|@]|A|$]]|$1|L|3|M|5|N|7|1O|8|@]|9|@]|A|$O|P]]|$1|Q|3|R|5|6|7|1P|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

<h3>1. To get an encoding parameter in Python 2:</h3>
If you only need to support Python 2.6 and 2.7 you can use <a href="https://docs.python.org/2/library/io.html#io.open" rel="noreferrer"><code>io.open</code></a> instead of <code>open</code>. <code>io</code> is the new io subsystem for Python 3, and it exists in Python 2,6 ans 2.7 as well. Please be aware that in Python 2.6 (as well as 3.0) it's implemented purely in python and very slow, so if you need speed in reading files, it's not a good option.
If you need speed, and you need to support Python 2.6 or earlier, you can use <a href="https://docs.python.org/2/library/codecs.html#codecs.open" rel="noreferrer"><code>codecs.open</code></a> instead. It also has an encoding parameter, and is quite similar to <code>io.open</code> except it handles line-endings differently.
<h3>2. To get a Python 3 <code>open()</code> style file handler which streams bytestrings:</h3>
<pre><code>open(filename, 'rb')
</code></pre>
Note the 'b', meaning 'binary'.

blocks|key|549198|text|这可能会起到作用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|549199|import+sys
if+sys.version_info[0]+>+2:
++++#+py3k
++++pass
else:
++++#+py2
++++import+codecs
++++import+warnings
++++def+open(file,+mode='r',+buffering=-1,+encoding=None,
+++++++++++++errors=None,+newline=None,+closefd=True,+opener=None):
++++++++if+newline+is+not+None:
++++++++++++warnings.warn('newline+is+not+supported+in+py2')
++++++++if+not+closefd:
++++++++++++warnings.warn('closefd+is+not+supported+in+py2')
++++++++if+opener+is+not+None:
++++++++++++warnings.warn('opener+is+not+supported+in+py2')
++++++++return+codecs.open(filename=file,+mode=mode,+encoding=encoding,
++++++++++++++++++++errors=errors,+buffering=buffering)|code-block|syntax|javascript|549200|然后你可以用python3的方式保存你的代码。|549201|请注意，newline、closefd、opener等一些API不起作用|offset|length|style|CODE|549202|entityMap^0|0|0|0|4|7|C|7|K|6|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]|$K|W|L|X|M|N]|$K|Y|L|Z|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|P|$]]

This may do the trick:

<pre><code>import sys
if sys.version_info[0] &gt; 2:
 # py3k
 pass
else:
 # py2
 import codecs
 import warnings
 def open(file, mode='r', buffering=-1, encoding=None,
 errors=None, newline=None, closefd=True, opener=None):
 if newline is not None:
 warnings.warn('newline is not supported in py2')
 if not closefd:
 warnings.warn('closefd is not supported in py2')
 if opener is not None:
 warnings.warn('opener is not supported in py2')
 return codecs.open(filename=file, mode=mode, encoding=encoding,
 errors=errors, buffering=buffering)
</code></pre>

Then you can keep you code in the python3 way.

Note that some APIs like <code>newline</code>, <code>closefd</code>, <code>opener</code> do not work

blocks|key|549237|text|这里有一种方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|549238|with+open("filename.txt",+"rb")+as+f:
++++contents+=+f.read().decode("UTF-8")|code-block|syntax|javascript|549239|下面是如何在编写时做同样的事情：|549240|with+open("filename.txt",+"wb")+as+f:
++++f.write(contents.encode("UTF-8"))|549241|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Here's one way:
<pre><code>with open(&quot;filename.txt&quot;, &quot;rb&quot;) as f:
 contents = f.read().decode(&quot;UTF-8&quot;)
</code></pre>
Here's how to do the same thing when writing:
<pre><code>with open(&quot;filename.txt&quot;, &quot;wb&quot;) as f:
 f.write(contents.encode(&quot;UTF-8&quot;))
</code></pre>

blocks|key|332748|text|如果你使用的是six，你可以试试这个，通过使用最新的Python3API，可以在Python2/3中运行：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|332749|import+six

if+six.PY2:
++++#+FileNotFoundError+is+only+available+since+Python+3.3
++++FileNotFoundError+=+IOError
++++from+io+import+open

fname+=+'index.rst'
try:
++++with+open(fname,+"rt",+encoding="utf-8")+as+f:
++++++++pass
++++++++#+do_something_with_f+...
except+FileNotFoundError:
++++print('Oops.')|code-block|syntax|javascript|332750|而且，Python2对放弃的支持只是删除了所有与six相关的东西。|332751|entityMap|0|LINK|mutability|MUTABLE|url|https://six.readthedocs.io/^0|7|3|7|3|0|0|0|O|3|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

If you are using <a href="https://six.readthedocs.io/" rel="nofollow noreferrer"><code>six</code></a>, you can try this, by which utilizing the latest Python 3 API and can run in both Python 2/3:

<pre class="lang-py prettyprint-override"><code>import six

if six.PY2:
 # FileNotFoundError is only available since Python 3.3
 FileNotFoundError = IOError
 from io import open

fname = 'index.rst'
try:
 with open(fname, "rt", encoding="utf-8") as f:
 pass
 # do_something_with_f ...
except FileNotFoundError:
 print('Oops.')
</code></pre>

And, Python 2 support abandon is just deleting everything related to <code>six</code>.

blocks|key|332875|text|不是一个通用的答案，但对于特定情况可能很有用，如果您对默认的python+2编码感到满意，但希望为python+3指定utf-8：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|332876|if+sys.version_info.major+>+2:
++++do_open+=+lambda+filename:+open(filename,+encoding='utf-8')
else:
++++do_open+=+lambda+filename:+open(filename)

with+do_open(filename)+as+file:
++++pass|code-block|syntax|javascript|332877|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Not a general answer, but may be useful for the specific case where you are happy with the default python 2 encoding, but want to specify utf-8 for python 3:
<pre><code>if sys.version_info.major &gt; 2:
 do_open = lambda filename: open(filename, encoding='utf-8')
else:
 do_open = lambda filename: open(filename)

with do_open(filename) as file:
 pass
</code></pre>

I have a Python codebase, built for Python 3, which uses Python 3 style open() with encoding parameter:

<a href="https://github.com/miohtama/vvv/blob/master/vvv/textlineplugin.py#L47" rel="noreferrer">https://github.com/miohtama/vvv/blob/master/vvv/textlineplugin.py#L47</a>

<pre><code> with open(fname, "rt", encoding="utf-8") as f:
</code></pre>

Now I'd like to backport this code to Python 2.x, so that I would have a codebase which works with Python 2 and Python 3.

What's the recommended strategy to work around <code>open()</code> differences and lack of encoding parameter?

Could I have a Python 3 <code>open()</code> style file handler which streams bytestrings, so it would act like Python 2 <code>open()</code>?

Backporting Python 3 open(encoding="utf-8") to Python 2

Python

我有一个Python代码库，是为Python 3构建的，它使用Python 3样式的open()和编码参数：    with open(fname, "rt", encoding="utf-8") as f:现在我想把这段代码移植到Python2.x上，这样我就有了一个适用于Python2和Python3的代码库。解决...

问将Python3开放(encoding=“utf-8”)反向移植到Python2
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问将Python3开放(encoding=“utf-8”)反向移植到Python2EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问将Python3开放(encoding=“utf-8”)反向移植到Python2
EN