function taking scalar or list argument

[Larry Bates]

You may want to take a look at isinstance() function.

def twice(x):
    if isinstance(x, list): return map(twice, x)
    if isinstance(x, (int, float, str)): return 2*x
    return None

print twice(3) # 6
print twice([1,4,9]) # [2,8,18]
print twice('*')

HTH,
Larry Bates
Syscon, Inc.

"beliavsky at aol.com" <beliavsky at 127.0.0.1:7501> wrote in message
news:412a2bce$1_1 at 127.0.0.1...
>
> I can define a function that transforms either a scalar or each element in
> a list as follows:
>
> def twice(x):
>     try:
>         return map(twice,x)
>     except:
>         return 2*x
>
> print twice(3) # 6
> print twice([1,4,9]) # [2,8,18]
>
> Is this good style? I intend to define many functions like this and want
> to use the right method. Thanks.
>
>
>
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