如何在 Python 中使用 utf-8 创建文件？

Question

我用open('test.txt', 'w')创建了一个新文件，它的字符集是binary。

>>> open('test.txt', 'w')
<open file 'test.txt', mode 'w' at 0x7f6b973704b0>

$ file -i test.txt.txt 
test2.txt: inode/x-empty; charset=binary

使用模块 codecs 分配具有指定字符集（例如 utf-8）的文件。但是，字符集仍然是 binary.

>>> codecs.open("test.txt", 'w', encoding='utf-8')
<open file 'test.txt', mode 'wb' at 0x7f6b97370540>

$ file -i test.txt 
test.txt: inode/x-empty; charset=binary

我写了一些东西到 test.txt，字符集是 us-ascii。

>>> fp. write ("wwwwwwwwwww")
>>> fp.close()

$ file -i test.txt 
test.txt: text/plain; charset=us-ascii

好的，现在，我写一些特殊字符（比如Arènes）。然而，

>>> fp = codecs.open("test.txt", 'w', encoding='utf-8')
>>> fp.write("Arènes")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/codecs.py", line 688, in write
    return self.writer.write(data)
  File "/usr/lib/python2.7/codecs.py", line 351, in write
    data, consumed = self.encode(object, self.errors)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 2: ordinal not in range(128)

更具体地说，我想将查询结果（使用python-mysqldb）保存到一个文件中。关键源码如下：

cur.execute("SELECT * FROM agency")

# Write to a file
with open('test.txt', 'w') as fp :
    for row in cur.fetchall() :
        s = '\t'.join(str(item) for item in row)
        fp.write(s + '\n')

现在，test.txt的字符集是iso-8859-1（一些法语字符，例如Arènes）。

因此，我使用codecs.open('test.txt', 'w', encoding='utf-8')创建一个文件。但是，遇到如下错误：

Traceback (most recent call last):
  File "./overlap_intervals.py", line 26, in <module>
    fp.write(s + '\n')
  File "/usr/lib/python2.7/codecs.py", line 688, in write
    return self.writer.write(data)
  File "/usr/lib/python2.7/codecs.py", line 351, in write
    data, consumed = self.encode(object, self.errors)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe9 in position 21: ordinal not in range(128)

如何在 Python 中使用 utf-8 创建文件？

Answer 1

空文件总是二进制文件。

$ touch /tmp/foo
$ file -i /tmp/foo 
/tmp/foo: inode/x-empty; charset=binary

放点东西进去就好了

$ cat > /tmp/foo 
Rübe
Möhre
Mähne
$ file -i /tmp/foo
/tmp/foo: text/plain; charset=utf-8

Python 将执行与 cat.

相同的操作

with open("/tmp/foo", "w") as f:
    f.write("Rübe\n")

检查一下：

$ cat /tmp/foo
Rübe
$ file -i /tmp/foo
/tmp/foo: text/plain; charset=utf-8

编辑：

使用 Python 2.7，您必须对 Unicode 字符串进行编码。

with open("/tmp/foo", "w") as f:
    f.write(u"Rübe\n".encode("UTF-8"))

Answer 2

在Python3中，还应该指定write()的编码：

with open("filepath", "w", encoding="utf-8") as f:
    f.write("Arènes")

如何在 Python 中使用 utf-8 创建文件？

How can I create a file with utf-8 in Python?

python

utf-8

character-encoding