PySerial与多个Python安装的问题

Question

我在我的Windows 7电脑上安装了Python 2.4.4和3.1.3。我想使用PySerial这个库。

我听说这个库是内置的，所以我在两个版本里都试着用import serial来导入。结果都出现了Import Error的错误。

然后我从这个页面下载了win32安装包。我运行了它，它为2.4.4安装成功了。（它说从注册表中找到了这个版本。）但是我没有选项可以切换到3.1.1版本。

接着我在2.4.4里遇到了以下错误：

>>> import serial

Traceback (most recent call last):
  File "<pyshell#0>", line 1, in -toplevel-
    import serial
  File "C:\Python24\Lib\site-packages\serial\__init__.py", line 19, in -toplevel-
    from serialwin32 import *
  File "C:\Python24\Lib\site-packages\serial\serialwin32.py", line 11, in -toplevel-
    import ctypes
ImportError: No module named ctypes

我查了一下ctypes，发现它从2.5.5版本开始就已经内置了。好的。

我下载了ctypes，然后运行python setup.py install来安装它。（在2.4.4下。）

结果是：

C:\path\to\ctypes-1.0.2>python setup.py install
running install
running build
running build_py
running build_ext
error: Python was built with Visual Studio 2003;
extensions must be built with a compiler than can generate compatible binaries.
Visual Studio 2003 was not found on this system. If you have Cygwin installed,
you can try compiling with MingW32, by passing "-c mingw32" to setup.py.

太好了。看起来这太麻烦了，所以我想试试Python 3.1.1。我把我的PATH环境变量改成包含C:\Python31\而不是C:\Python24。

我重启了命令行，然后在pyserial上运行python setup.py install：

C:\path\to\pyserial-2.5>python setup.py install
running install
running build
running build_py
running build_scripts
running install_lib
running install_scripts

C:\path\to\pyserial-2.5>

有趣。我接着在Python 3.1.1的IDLE里尝试import serial，但又遇到了标准的ImportError。嗯。

这是怎么回事？我是不是做错了什么？

更新：我尝试用3.1.1运行setup.py install：

c:\path\to\pyserial-2.5>c:\python31\python.exe setup.py install
running install
running build
running build_py
running build_scripts
creating build\scripts-3.1
copying and adjusting examples\miniterm.py -> build\scripts-3.1
running install_lib
creating c:\python31\Lib\site-packages\serial
copying build\lib\serial\loopback_connection.py -> c:\python31\Lib\site-packages
\serial
copying build\lib\serial\rfc2217.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\serialcli.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\serialjava.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\serialposix.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\serialutil.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\serialwin32.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\sermsdos.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\socket_connection.py -> c:\python31\Lib\site-packages\s
erial
copying build\lib\serial\win32.py -> c:\python31\Lib\site-packages\serial
copying build\lib\serial\__init__.py -> c:\python31\Lib\site-packages\serial
byte-compiling c:\python31\Lib\site-packages\serial\loopback_connection.py to lo
opback_connection.pyc
  File "c:\python31\Lib\site-packages\serial\loopback_connection.py", line 101
    except ValueError, e:
                     ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\rfc2217.py to rfc2217.pyc
  File "c:\python31\Lib\site-packages\serial\rfc2217.py", line 370
    except Exception, msg:
                    ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\serialcli.py to serialcli.py
c
  File "c:\python31\Lib\site-packages\serial\serialcli.py", line 39
    except Exception, msg:
                    ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\serialjava.py to serialjava.
pyc
  File "c:\python31\Lib\site-packages\serial\serialjava.py", line 67
    except Exception, msg:
                    ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\serialposix.py to serialposi
x.pyc
  File "c:\python31\Lib\site-packages\serial\serialposix.py", line 64
    50:      0000001,
                   ^
SyntaxError: invalid token

byte-compiling c:\python31\Lib\site-packages\serial\serialutil.py to serialutil.
pyc
  File "c:\python31\Lib\site-packages\serial\serialutil.py", line 510
    except TypeError, err:
                    ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\serialwin32.py to serialwin3
2.pyc
byte-compiling c:\python31\Lib\site-packages\serial\sermsdos.py to sermsdos.pyc
byte-compiling c:\python31\Lib\site-packages\serial\socket_connection.py to sock
et_connection.pyc
  File "c:\python31\Lib\site-packages\serial\socket_connection.py", line 49
    except Exception, msg:
                    ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\win32.py to win32.pyc
  File "c:\python31\Lib\site-packages\serial\win32.py", line 164
    MAXDWORD = 4294967295L # Variable c_uint
                         ^
SyntaxError: invalid syntax

byte-compiling c:\python31\Lib\site-packages\serial\__init__.py to __init__.pyc
running install_scripts
creating c:\python31\Scripts
copying build\scripts-3.1\miniterm.py -> c:\python31\Scripts
running install_egg_info
Writing c:\python31\Lib\site-packages\pyserial_py3k-2.5-py3.1.egg-info


c:\path\to\pyserial-2.5>

嗯……看起来我使用了错误版本的pyserial。这个下载页面上显示2.5是最新的版本。奇怪。

更新 2：我检查并修复了所有的语法错误，但开始遇到导入错误。在__init__.py里，我把：

if os.name == 'nt': #sys.platform == 'win32':
    from serialwin32 import *
elif os.name == 'posix':
    from serialposix import *
elif os.name == 'java':
    from serialjava import *

改成：

if os.name == 'nt': #sys.platform == 'win32':
    from .serialwin32 import *
elif os.name == 'posix':
    from .serialposix import *
elif os.name == 'java':
    from .serialjava import *

现在我在serialwin32.py里又遇到了一个错误：

>>> import serial
Traceback (most recent call last):
  File "<pyshell#4>", line 1, in <module>
    import serial
  File "C:\Python31\lib\site-packages\serial\__init__.py", line 19, in <module>
    from .serialwin32 import *
  File "C:\Python31\lib\site-packages\serial\serialwin32.py", line 12, in <module>
    import win32
ImportError: No module named win32

我尝试使用.modulename的语法，但那样无法编译。

我还可以做些什么呢？我很难相信这个代码是为了在Python 3上运行的。（也许我下载了错误的版本？）

windows 版本兼容性环境变量安装包库管理导入错误语法错误 pyserial

PySerial与多个Python安装的问题

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