检查Python版本:Python -V或Python——version或apt-cache policy Python

你也可以运行whereis python查看安装了多少个版本。

只是为了好玩，下面是在CPython 1.0-3.7b2, Pypy, Jython和Micropython上的一种方法。在现代代码中，这更像是一种新奇的做法。我将其作为http://stromberg.dnsalias.org/~strombrg/pythons/的一部分编写，这是一个脚本，用于在多个版本的python上同时测试一段代码，因此您可以轻松地了解哪些python特性与哪些版本的python兼容:

via_platform = 0
check_sys = 0
via_sys_version_info = 0
via_sys_version = 0
test_sys = 0
try:
    import platform
except (ImportError, NameError):
    # We have no platform module - try to get the info via the sys module
    check_sys = 1

if not check_sys:
    if hasattr(platform, "python_version"):
        via_platform = 1
    else:
        check_sys = 1

if check_sys:
    try:
        import sys
        test_sys = 1
    except (ImportError, NameError):
        # just let via_sys_version_info and via_sys_version remain False - we have no sys module
        pass

if test_sys:
    if hasattr(sys, "version_info"):
        via_sys_version_info = 1
    elif hasattr(sys, "version"):
        via_sys_version = 1
    else:
        # just let via_sys remain False
        pass

if via_platform:
    # This gives pretty good info, but is not available in older interpreters.  Also, micropython has a
    # platform module that does not really contain anything.
    print(platform.python_version())
elif via_sys_version_info:
    # This is compatible with some older interpreters, but does not give quite as much info.
    print("%s.%s.%s" % sys.version_info[:3])
elif via_sys_version:
    import string
    # This is compatible with some older interpreters, but does not give quite as much info.
    verbose_version = sys.version
    version_list = string.split(verbose_version)
    print(version_list[0])
else:
    print("unknown")

从stdlib中使用平台的python_version:

from platform import python_version
print(python_version())

# 3.9.2

这只返回2.7 3.6或3.9

import sys
current_version = ".".join(map(str, sys.version_info[0:2]))

这是你通常需要的…

在Windows操作系统下，通过在命令提示符中输入以下命令，验证命令的Python版本

c:\>python -V
Python 2.7.16

c:\>py -2 -V
Python 2.7.16

c:\>py -3 -V
Python 3.7.3

此外，要查看每个Python版本的文件夹配置，请运行以下命令:

For Python 2,'py -2 -m site'
For Python 3,'py -3 -m site'

就像Seth说的，主脚本可以检查sys。Version_info(但请注意，它直到2.0才出现，所以如果你想支持旧版本，你需要检查sys模块的另一个version属性)。

但是，您仍然需要注意不要在文件中使用旧版本Python中没有的任何Python语言特性。例如，这在Python 2.5及更高版本中是允许的:

try:
    pass
except:
    pass
finally:
    pass

但在较旧的Python版本中不能工作，因为只能使用except OR最终匹配try。所以为了与旧版本的Python兼容，你需要写:

try:
    try:
        pass
    except:
        pass
finally:
    pass