[Tutor] How to run this block of code dozens of times

[Oscar Benjamin]

On 2012-09-17, Emile van Sebille <emile at fenx.com> wrote:
>
> Be sure you don't at some point depend on _ having a specific value 
> however, as return values of functions are given the _ name in the 
> absense of a designated label for the returned value:
>
> ActivePython 2.6.6.15 (ActiveState Software Inc.) based on
> Python 2.6.6 (r266:84292, Aug 24 2010, 16:01:11) [MSC v.1500 32 bit 
> (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
> >>> def test(): return True
> ...
> >>> _
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> NameError: name '_' is not defined
> >>> test()
> True
> >>> _
> True
> >>>

This only happens as a convenience in interactive mode. In scripts or modules
the _ identifier has no significance except for the convention that it is a
value you don't care about.

$ cat tmp.py
def test(): return True
test()
_
$ python tmp.py
Traceback (most recent call last):
  File "tmp.py", line 3, in <module>
    _
NameError: name '_' is not defined

Oscar