在Mac上的Shell中导入模块

Question

I've recently started reading the 4th edition of Mark Lutz' book "Learning Python". I downloaded the latest version of Python (v3.7) and IDLE, and I'm operating on a Mac. I am having trouble trying to import modules. On page 54, it says to create a script, threenames.py, with the following code:

a = 'dead' 
b = 'parrot' 
c = 'sketch'

I've saved this in my Desktop. Next I open up a shell:

import threenames

and the output should be dead parrot sketch However, I'm getting the error message:

Traceback (most recent call last):

File "< pyshell#0 >", line 1, in < module >

import threenames

ModuleNotFoundError: No module named 'threenames'

my sys.path is ['', '/Users/xxxx/Documents', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python37.zip', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages']

Answer 1

Since your Desktop folder is at /Users/xxx/Desktop and is not listed in sys.path you could either move the file to /Users/xxx/Documents (the Documents folder in your home directory) or do a cd ~/Desktop inside your shell before starting python, because sys.path contains '' which refers to the current working directory.

However just importing that module will not make those variables accessible in the shell, you'd have to explicitly import them:

from threenames import a, b, c

Answer 2

The file have to be in your current work directory. Then it is no problem to import it. There are two ways to achieve this.

1. Just open your python shell from the same folder your .py file is stored. The work directory is always set to the place from where you started the python shell.

2. Just change your working directory in code. Just call:

   import os os.chdir("/directory/with/your/pyfile/")