Re: Count using pattern on two different matrices

*To*: mathgroup at smc.vnet.net*Subject*: [mg57085] Re: [mg57079] Count using pattern on two different matrices*From*: DrBob <drbob at bigfoot.com>*Date*: Sun, 15 May 2005 03:03:38 -0400 (EDT)*Organization*: Deep Space Corps of Engineers*References*: <200505140858.EAA09500@smc.vnet.net>*Reply-to*: drbob at bigfoot.com*Sender*: owner-wri-mathgroup at wolfram.com

Length@Cases[Transpose@{L1, L2}, {{_, False}, {_, _, True}}] Bobby On Sat, 14 May 2005 04:58:25 -0400 (EDT), Lee Newman <leenewm at umich.edu> wrote: > 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 > > > > -- DrBob at bigfoot.com

**References**:**Count using pattern on two different matrices***From:*Lee Newman <leenewm@umich.edu>