Re: fast way of appending x zeros to a list?
- To: mathgroup at smc.vnet.net
- Subject: [mg79106] Re: fast way of appending x zeros to a list?
- From: Peter Breitfeld <phbrf at t-online.de>
- Date: Thu, 19 Jul 2007 03:21:10 -0400 (EDT)
- References: <f7ke8n$508$1@smc.vnet.net>
kristoph schrieb:
> Dear all,
>
> I'm looking for a fast way to append 0's to a list. Unfortunately, I
> append a variable number of 0's to a list which is generated by a
> For[...]-loop. Therefore, PadLeft[...] is not variable enough to
> append exactly x zeros to the list.
>
> At the moment I use: Do[PrependTo[data,0],{K}] where the K depends on
> certain factors.
AppendTo and PrependTo are known to be very slow. It's better to
build up a nested list an Flatten it:
Do[data={0,data},{K}]; Flatten[data]
Gruss Peter
--
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Peter Breitfeld, Bad Saulgau, Germany -- http://www.pBreitfeld.de
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