Re: Mapping to Create Nested Loops
- To: mathgroup at smc.vnet.net
- Subject: [mg119395] Re: Mapping to Create Nested Loops
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Wed, 1 Jun 2011 07:27:29 -0400 (EDT)
- Reply-to: hanlonr at cox.net
GatherBy[myArray, #[[3]] &]
GatherBy[#, #[[3]] &] & /@ myListOfArrays
Bob Hanlon
---- Gregory Lypny <gregory.lypny at videotron.ca> wrote:
=============
Hello everyone,
I'm trying to learn how to use pure functions and mapping to create what amounts to nested loops.
Suppose I have a 50 x 6 array called myArray. The third element of each row is the word red, blue, or green. If I wanted to break down the array into three according to the value of the third element, I could do this:
Cases[myArray, {__, __, #, __, __, __}] & /@ {red, blue, green}
But what if I needed to do this for more than one array? Suppose I had three 50 x 6 arrays as
myListOfArrays = {myArray1, myArray2, myArray3} or perhaps the arrays might be imported from files.
Regards,
Gregory