Re:expanding a list - Thanks!
- To: mathgroup at smc.vnet.net
- Subject: [mg42696] Re:[mg42593] expanding a list - Thanks!
- From: Alan Kelly <Alan.Kelly at tcd.ie>
- Date: Mon, 21 Jul 2003 05:15:23 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Deal All - I posted my thanks to two respondents (see below) on
Thursday last - but by Friday afternoon I had had close to thirty
replies along the same lines as given below - too many to reply to
individually, so many thanks to all of you for taking the trouble to
answer my question.
best wishes,
Alan Kelly
>My thanks to Mihajlo Vanevic and Bob Hanlon for answering my question
>(see below). I asked for an elegant and efficient solution and
>that's what I got!
>
>Mihajlo suggested:
>
>MapThread[Table[#1, {#2}] &, {plist, flist}]
>or
>Flatten@MapThread[Table[#1, {#2}] &, {plist, flist}]
>
>and Bog suggested:
>Flatten[Table[#[[1]], {#[[2]]}] & /@ Transpose[{plist, flist}]]
>
>Again, many thanks to both. Now all I have to do is understand how
>these actually work!!
>Alan Kelly
>
>
>My original question
>_______________________________________________________________
>Hi all,
>I believe that this is a rather elementary question, but I am not
>aware of a simple, elegant and efficient solution. I have searched
>the MathGroup archive, but with no success.
>
>I have two lists - both of the same length. The first contains a
>list of probabilities. For example, suppose the list length is 4
>(although in practice it would be much longer) and is of the
>following form:
>plist = {0.252, 0.252, 0.257, 0.235}.
>The second contains a list of integers:
>flist = {7,5,6,4}.
>I wish to take the first element of plist and replicate that value
>using the first element of flist. Similarly for the remaining
>elements.
>I should finish with a list of length 7+5+6+4 or 22.
>Any suggestion please.
>Many thanks,
>Alan Kelly
>Trinity College Dublin
>
>+-------------------------------------------------------+
> Dr. Alan Kelly E-mail akelly at mail.tcd.ie
> Biostatistician Phone: +353-1-608 1385 or 608 1087
> Fax: +353-1-403 1211 or 403 1212
>
>
>
>Director of the Small Area Health Research Unit
>
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>
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>Ireland
>
>
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>
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