[R] counting the number of rows that satisfy a certain criteria

Kate Ignatius kate.ignatius at gmail.com
Sat Jun 21 17:34:59 CEST 2014


Thanks!

On Sat, Jun 21, 2014 at 11:05 AM, Jorge I Velez
<jorgeivanvelez at gmail.com> wrote:
> Hi Kate,
>
> You could try
>
> sum(X[, 1] == 1 &  X[, 2] == 1)
>
> where X is your data set.
>
> HTH,
> Jorge.-
>
>
>
> On Sun, Jun 22, 2014 at 12:57 AM, Kate Ignatius <kate.ignatius at gmail.com>
> wrote:
>>
>> I have 4 columns, and about 300K plus rows with 0s and 1s.
>>
>> I'm trying to count how many rows satisfy a certain criteria... for
>> instance, how many rows are there that have the first column == 1 as
>> well as the second column == 1.
>>
>> I've tried using rowSums and colSums but it keeps giving me this type of
>> error:
>>
>> Error in rowSums(X[1] == 1 & X[2] == 1) :
>>   'x' must be an array of at least two dimensions
>>
>> Thanks in advance!
>>
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>
>



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