reducing the time of constructing a List

*To*: mathgroup at smc.vnet.net*Subject*: [mg57533] reducing the time of constructing a List*From*: marloo3 at mail15.com*Date*: Tue, 31 May 2005 05:00:08 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

please, what is the best way to reduce the timing of the following lines, the source of data is: dat = Table[Random[Integer, {0, 10}], {100000}]; and the purpose is to construct the List lst in the following way: For[i = 1, i <= 100000, If [dat[[i]] == 1, lst = Join[lst, {1}], lst = Join[lst, {0}]]; i++]; // Timing Out[]= {226.07 Second, Null} on the P4 celeron 2 Ghz , memory 382 MB ram thanks