multiply utple or list

[Jim Red]

what is the best way to multiply a tuple or list by a given value

exp.
multiply (4, 5) by 2 => (8, 10)

cheers

jr

[Karl Scalet]

Re: multiply utple or list

Jim Red wrote:[color=blue]
> what is the best way to multiply a tuple or list by a given value
>
> exp.
> multiply (4, 5) by 2 => (8, 10)
>
> cheers
>
> jr[/color]

i.e.:
[color=blue][color=green][color=darkred]
>>> import operator
>>> [ operator.mul(x, 2) for x in (4,5)][/color][/color][/color]

regards,
Karl

[P@draigBrady.com]

Re: multiply utple or list

Jim Red wrote:[color=blue]
> what is the best way to multiply a tuple or list by a given value
>
> exp.
> multiply (4, 5) by 2 => (8, 10)[/color]

something like this?

import types
def multiply_sequen ce(sequence, multiplier):
new_sequence = map(lambda item: item*multiplier , sequence)
if type(sequence) == types.TupleType :
return tuple(new_seque nce)
elif type(sequence) == types.ListType:
return new_sequence

--
Pádraig Brady - http://www.pixelbeat.org

[Diez B. Roggisch]

Re: multiply utple or list

> >>> import operator[color=blue][color=green][color=darkred]
> >>> [ operator.mul(x, 2) for x in (4,5)][/color][/color][/color]

Why not simply * ?

[ x * 2 for x in (4,5)]

And you might surround it by tuple to gain a tuple

tuple([ x * 2 for x in (4,5)])

Another way would be to use Numeric

import Numeric
a = Numeric.array(( 10,2), Numeric.Float32 )
a = a * 2


--
Regards,

Diez B. Roggisch

[Karl Scalet]

Re: multiply utple or list

Diez B. Roggisch wrote:
[color=blue][color=green][color=darkred]
>> >>> import operator
>> >>> [ operator.mul(x, 2) for x in (4,5)][/color][/color]
>
>
> Why not simply * ?
>
> [ x * 2 for x in (4,5)]
>[/color]

oops, of course. I had the map function in mind,
which only accepts a function, but this would come
to something like:

li=(4,5)
map(operator.mu l, li, (2,)*len(li))

and is certainly worse then list comprehension :-)

regards,
Karl