Re: Re: Replace non-numeric values in a list
- To: mathgroup at smc.vnet.net
- Subject: [mg88812] Re: [mg88786] Re: [mg88745] Replace non-numeric values in a list
- From: Syd Geraghty <sydgeraghty at mac.com>
- Date: Sat, 17 May 2008 05:30:39 -0400 (EDT)
- References: <12929374.1210891275393.JavaMail.root@m08> <200805160934.FAA01192@smc.vnet.net>
Hi Adel et al,
There were a lot of interesting replies to this question.
I thought you might be interested in speed of some of them on a big
list.
Bobby was fastest followed by Szabolcs.
bigriffledlist = Riffle[RandomInteger[{1, 5}, 5000000], {x, y, z}];
newlistbob = Replace[bigriffledlist, {x_?NumericQ -> x, x_ -> 0},
1]; // Timing (* DrMajorBob *)
{5.81391, Null}
newlistszabolcs = Replace[bigriffledlist, x_ /; ! NumericQ[x] -> 0,
1]; // Timing (*Szabolcs Horvat*)
{8.11852, Null}
newlistszabolcs == newlistbob // Timing
{0.090427, True}
Other notables were.
newlist = Map[(If[NumericQ[#], #, 0] &), bigriffledlist]; // Timing
(*Bob Hanlon*)
{10.2462, Null}
newlist = Replace[bigriffledlist, _?(Not[NumericQ[#]] &) -> 0, 1]; //
Timing (*Bob Hanlon*)
{11.9771, Null}
Cheers ... Syd
Syd Geraghty B.Sc, M.Sc.
sydgeraghty at mac.com
My System
Mathematica 6.0.2.1 for Mac OS X x86 (64 - bit) (March 13, 2008)
MacOS X V 10.5.2
MacBook Pro 2.33 Ghz Intel Core 2 Duo 2GB RAM
On May 16, 2008, at 2:34 AM, DrMajorBob wrote:
> list = {a, 1, 2, b, 3};
> Replace[list, {x_?NumericQ -> x, x_ -> 0}, 1]
>
> {0, 1, 2, 0, 3}
>
> or
>
> Replace[list, x_ /; ! NumericQ[x] -> 0, 1]
>
> {0, 1, 2, 0, 3}
>
> Bobby
>
> On Thu, 15 May 2008 06:50:03 -0500, Adel Elsabbagh <aelsabbagh at gmail.com
> >
> wrote:
>
>> Dear all,
>>
>> I have a list that contains numeric and non-numeric values
>> list = { a, 1, 2, b, 3};
>> How can I replace non-numeric values with zeros?
>> Thanks!
>>
>
>
>
> --
>
> DrMajorBob at longhorns.com
>
- References:
- Re: Replace non-numeric values in a list
- From: DrMajorBob <drmajorbob@att.net>
- Re: Replace non-numeric values in a list