本文介绍了为什么这在 Python IDLE shell 中有效,但当我从命令提示符将它作为 Python 脚本运行时却无效?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
这适用于 Python 3.3.2 Shell
Python 3.3.2 Shell 内部
>>>导入日期时间>>>打印(日期时间.日期时间.utcnow())2013-07-09 19:40:32.532341太好了!然后我写了一个名为datetime.py"的简单文本文件
Datetime.py 内部
#日期时间导入日期时间打印(日期时间.日期时间.utcnow())#Prints GMT,它被命名为通用协调时间# 这是 UTC 因为在法语中它类似于# Universahl Tyme Coordinatay#输出类似 2013-07-09 15:15:19.695531 的内容
证明文件存在
C:\Python33\myscripts>ls__pycache__ ex1.out ex2.out ex3.py helloworld.py read1.pydatetime.py ex1.py ex2.py first.py pythonintoimportexport.py test.py
这就是它变得神秘的地方!
C:\Python33\myscripts>python datetime.py回溯(最近一次调用最后一次):文件datetime.py",第 2 行,在 <module> 中导入日期时间文件C:\Python33\myscripts\datetime.py",第 3 行,在 <module> 中打印(日期时间.日期时间.utcnow())AttributeError: 'module' 对象没有属性 'utcnow'
问题
为什么相同的代码可以在 Python Shell 中运行,但在作为脚本运行时却不能运行?
解决方案
问题是文件是递归导入自身,而不是导入内置模块datetime
:
演示:
$ cat datetime.py导入日期时间打印日期时间.__文件__$ python datetime.py/home/monty/py/datetime.pyc/home/monty/py/datetime.pyc
发生这种情况是因为搜索了模块 按此顺序:
- 包含输入脚本的目录(或当前目录).
- PYTHONPATH(目录名称列表,语法与shell 变量 PATH).
- 依赖于安装的默认值.
只需将 datetime.py
的名称更改为其他名称即可.
This works in the Python 3.3.2 Shell
Inside the Python 3.3.2 Shell
>>> import datetime
>>> print(datetime.datetime.utcnow())
2013-07-09 19:40:32.532341
That's great! I then wrote a simple text file named "datetime.py"
Inside Datetime.py
#Date time
import datetime
print(datetime.datetime.utcnow())
#Prints GMT, which is named Universal Coordinated Time
# Which is UTC because in French it's something like
# Universahl Tyme Coordinatay
#Outputs something like 2013-07-09 15:15:19.695531
Proving that the file exists
C:\Python33\myscripts>ls
__pycache__ ex1.out ex2.out ex3.py helloworld.py read1.py
datetime.py ex1.py ex2.py first.py pythonintoimportexport.py test.py
Here is where it gets mysterious!
C:\Python33\myscripts>python datetime.py
Traceback (most recent call last):
File "datetime.py", line 2, in <module>
import datetime
File "C:\Python33\myscripts\datetime.py", line 3, in <module>
print(datetime.datetime.utcnow())
AttributeError: 'module' object has no attribute 'utcnow'
Question
Why does the same code work in the Python Shell, but not when run as a script?
解决方案
The problem is that file is recursively importing itself, instead of importing the built-in module datetime
:
Demo:
$ cat datetime.py
import datetime
print datetime.__file__
$ python datetime.py
/home/monty/py/datetime.pyc
/home/monty/py/datetime.pyc
This happens because the module is searched in this order:
- the directory containing the input script (or the current directory).
- PYTHONPATH (a list of directory names, with the same syntax as theshell variable PATH).
- the installation-dependent default.
Simply change the name of datetime.py
to something else.
这篇关于为什么这在 Python IDLE shell 中有效,但当我从命令提示符将它作为 Python 脚本运行时却无效?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!