Count using pattern on two different matrices

*To*: mathgroup at smc.vnet.net*Subject*: [mg57079] Count using pattern on two different matrices*From*: Lee Newman <leenewm at umich.edu>*Date*: Sat, 14 May 2005 04:58:25 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I have two matrices with an equal number of rows, but not necessarily columns, for example: L1= {{True,False},{False, True},{False, False}, etc.....} ; L2= {{True,False,False},{True, True,True},{False, True,False}, etc.....} ; I would like to compute a count of the number of rows in which one of the columns of L1 meets some criterion, and one of the columns of L2 meets some criterion, i.e. If L1[[row,2 ]]==False and L2[[row,3]]==True then this row contributes 1 to the count. I suspect that there is an elegant way to do this, perhaps using Count[] and MapThread, but I can't figure it out other than resorting to a rather clumsy For or Do loop that would check line by line and maintain a counter. Any help would be appreciated, Lee

**Follow-Ups**:**Re: Count using pattern on two different matrices***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**Re: Count using pattern on two different matrices***From:*Chris Chiasson <chris.chiasson@gmail.com>

**Re: Count using pattern on two different matrices***From:*DrBob <drbob@bigfoot.com>