A simple print cannot run in Python Shell

[Steven D'Aprano]

On Monday 01 June 2015 17:50, fl wrote:

> Hi,
> 
> When I try the following (They are saved in a main.py file)
> 
> #!/usr/bin/python
> print r'C:\\nowhere'

Aside: Don't use raw strings for file names. They aren't intended for file 
names, and while they will *usually* work, some day you will try something 
like this:

    path = r'C:\\path\ending\with\slash\'

and then you will discover that raw strings aren't for file names.

So just get used to using forward slashes.



> It works as the tutorial, i.e. it echoes in a Windows 7
> command console:
> 
> 
> C:\\nowhere


How do you run it in Windows 7? The hashbang line

    #!/usr/bin/python

is for Linux and Unix, and won't work on Windows. So you must be doing 
something to execute the file. What is that?


> When I run the following command in a Python 2.7.9 Shell on Windows 7,
>
> print r'C:\\nowhere'
> 
> 
> 
> It has error:
> 
>>>> print r'C:\\nowhere'
> SyntaxError: invalid syntax

In the future, please copy and paste the *complete* traceback, as that may 
include more information. Syntax errors usually include a line pointing to 
the location of the error, or just past it:

py> print foo
  File "<stdin>", line 1
    prin foo
           ^
SyntaxError: invalid syntax


Notice the line with the ^ caret?



> What is the problem? Why does it behave different at .py file
> and Python Shell?

Are you absolutely sure the Python Shell is running Python 2.7? It looks 
like you are running Python 3. What does this display in the shell?

import sys
sys.version


Otherwise you must have run this at some point:

from __future__ import print_function


If you exit the shell, and start it up again, that should reset import.

If not, then there is a possibility that your version of Python is 
configured to do the __future__ import. Try this:

print
print_function

What do you see? If you get an error, copy and paste the *entire* traceback.


-- 
Steve