How is the performance of Position[] ..
- To: mathgroup at smc.vnet.net
- Subject: [mg7041] How is the performance of Position[] ..
- From: cmchung at se.cuhk.edu.hk (Chung Cheong Ming)
- Date: Sat, 3 May 1997 22:04:37 -0400 (EDT)
- Organization: Engineering Faculty CUHK
- Sender: owner-wri-mathgroup at wolfram.com
I've got a problem, see anyone can shed some light.
I have an array (a list of sublists) with the following structure,
ARRAY = { { {a11a,a11b}, a12, ...},
{ {a21a,a21b}, a22, ...},
{ {a31a,a31b}, a32, ...},
:
:
{ {am1a,am2b}, am2, ...}}
|<----- n elements ----->|
Thus I have a m by n matrix with the first element in each sublist as
a 2-element list. My question is if I know a particular pair of this
first element eg. {1000,2000}, how will be the computation of Position[]
if I want to use this as a key to extract the row number where
{1000,2000} situates in ARRAY.
If anyone know of any formal literature (maybe Mathematica technical
report), I would be very appreciated.
Thanks
Joseph