       Re: Count using pattern on two different matrices

• To: mathgroup at smc.vnet.net
• Subject: [mg57082] Re: [mg57079] Count using pattern on two different matrices
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sun, 15 May 2005 03:03:35 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```L1=Table[Random[Integer]==1,{5},{2}]

{{True, False}, {True, True}, {True, False}, {True, True},
{True, False}}

L2=Table[Random[Integer]==1,{5},{3}]

{{False, True, True}, {True, True, True},
{False, True, True}, {False, True, True},
{False, True, False}}

_?(#[]==False&&#[]==True&)]

2

_?(Not[#[]]&&#[]&)]

2

Bob Hanlon

>
> From: Lee Newman <leenewm at umich.edu>
To: mathgroup at smc.vnet.net
> Date: 2005/05/14 Sat AM 04:58:25 EDT
> Subject: [mg57082] [mg57079] Count using pattern on two different matrices
>
> 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
>
>

```

• Prev by Date: Re: Re: Hold problems with FindRoot
• Next by Date: Re: DSolve and K\$31, i am puzzled
• Previous by thread: Re: Count using pattern on two different matrices
• Next by thread: Re: Count using pattern on two different matrices