[Tutor] Fwd: What's in a name?

[Mark Lawrence]

On 03/01/2014 06:18, Keith Winston wrote:
> Shoot: I sent this response directly to Mark, without even trimming.
> Here it is to the list...
>
> Hi Mark: sorry for unclarity. I am probably going to make a hash of
> explaining this, but here goes:
>
> I want to iterate a variable across a list of objects, and print both
> the outputs (wrong word) of said objects, and the name of the objects.
> Those objects might be lists, or functions, as examples.
>
> As a non-iterative example, something like this:
>
> a = "max"
> print(eval(a)(3,4), a)  # output: 4 max
>
> That's the only way I can figure out how to make it work. Here's an
> actual code snippet, watch for stype:
>
>      for func in ["mean", "max", "min", "variance", "stdev"]:
>              print("{moves:9.2f} {chutes:12.2f} {ladders:13.2f}
> {stype}".format(
>                  moves=eval(func)(tgset[1] for tgset in garray),
>                  chutes=eval(func)(tgset[2] for tgset in garray),
>                  ladders=eval(func)(tgset[3] for tgset in garray),
>                  stype=func
>                  ))
>

You enjoy making life difficult for yourself :)  You've assigned strings 
to the name func, just assign the functions themselves?  Like.

for func in max, min:
     print(func.__name__, func(range(5)))

Output.

max 4
min 0

> Output:
>       4.67         0.21          0.79 mean
>      28.00         1.00          1.00 max
>       1.00         0.00          0.00 min
>      23.69         0.17          0.17 variance
>       4.87         0.41          0.41 stdev
>
> I appreciate the point about eval being dangerous, though the second
> line in your reference does say "if you accept strings to evaluate from
> untrusted input". Still, I can appreciate how eval() could go off the
> rails. Is there another way I can do what I want? Sorry for not testing
> the code I posted earlier.
>

-- 
My fellow Pythonistas, ask not what our language can do for you, ask 
what you can do for our language.

Mark Lawrence