目标是不断地阅读stdin
并强制执行utf8
在Python2和Python3中。
我尝试过以下解决方案:
- 以与 python2 和 python3 兼容的方式将字节写入标准输出 https://stackoverflow.com/questions/23932332/writing-bytes-to-standard-output-in-a-way-compatible-with-both-python2-and-pyth/23932488#23932488
- Python 3:如何指定标准输入编码 https://stackoverflow.com/questions/16549332/python-3-how-to-specify-stdin-encoding/16549381#16549381
我试过了:
#!/usr/bin/env python
from __future__ import print_function, unicode_literals
import io
import sys
# Supports Python2 read from stdin and Python3 read from stdin.buffer
# https://stackoverflow.com/a/23932488/610569
user_input = getattr(sys.stdin, 'buffer', sys.stdin)
# Enforcing utf-8 in Python3
# https://stackoverflow.com/a/16549381/610569
with io.TextIOWrapper(user_input, encoding='utf-8') as fin:
for line in fin:
# Reads the input line by line
# and do something, for e.g. just print line.
print(line)
该代码在 Python3 中工作,但在 Python2 中,TextIOWrapper 没有读取函数,它会抛出:
Traceback (most recent call last):
File "testfin.py", line 12, in <module>
with io.TextIOWrapper(user_input, encoding='utf-8') as fin:
AttributeError: 'file' object has no attribute 'readable'
那是因为在 Python 中user_input
, i.e. sys.stdin.buffer
is an
_io.BufferedReader
对象及其属性有readable
:
<class '_io.BufferedReader'>
['__class__', '__del__', '__delattr__', '__dict__', '__dir__', '__doc__', '__enter__', '__eq__', '__exit__', '__format__', '__ge__', '__getattribute__', '__getstate__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__lt__', '__ne__', '__new__', '__next__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '_checkClosed', '_checkReadable', '_checkSeekable', '_checkWritable', '_dealloc_warn', '_finalizing', 'close', 'closed', 'detach', 'fileno', 'flush', 'isatty', 'mode', 'name', 'peek', 'raw', 'read', 'read1', 'readable', 'readinto', 'readinto1', 'readline', 'readlines', 'seek', 'seekable', 'tell', 'truncate', 'writable', 'write', 'writelines']
而在Python2中user_input
是一个文件对象,它的属性没有readable
:
<type 'file'>
['__class__', '__delattr__', '__doc__', '__enter__', '__exit__', '__format__', '__getattribute__', '__hash__', '__init__', '__iter__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'close', 'closed', 'encoding', 'errors', 'fileno', 'flush', 'isatty', 'mode', 'name', 'newlines', 'next', 'read', 'readinto', 'readline', 'readlines', 'seek', 'softspace', 'tell', 'truncate', 'write', 'writelines', 'xreadlines']