[R] counting columns that match criteria

[jim holtman]

try this:

> x
  Col1 Col2 Col3 Col4
1    1    1    1    1
2    2    1    1    1
3    4    1    4    1
4    3    3    3    3
> apply(x, 1, function(a) sum(a > 1))
[1] 0 1 2 4
> x$count <- apply(x, 1, function(a) sum(a > 1))
> x
  Col1 Col2 Col3 Col4 count
1    1    1    1    1     0
2    2    1    1    1     1
3    4    1    4    1     2
4    3    3    3    3     4
>


On Thu, Nov 10, 2011 at 10:24 AM, JL Villanueva <jlpostage at gmail.com> wrote:
> Hi,
>
> I am a little new in R but I'm finding it extremely useful :)
>
> Here's my tiny question:
>
> I've got a table with a lot of columns. What I am interested now is to
> evaluate how many of 4 columns have a value greater than 1.
> I think it can be done with subset() but it will take a very long condition
> and become unfeasible if I want to compare more than 4 columns.
>
> I put here a small example
>
> Col1  Col2  Col3  Col 4
> 1        1       1       1             <-0 columns greater than 1
> 2        1       1       1             <-1 column greater than 1
> 4        1       4      1              <-2 columns greater than 1
> 3        3       3       3             <-3 columns greater than 1
>
> Then I want to filter by that number, my idea is to create a new column
> storing the number calculated and subset() by it.
>
> Any hints?
> Thanks in advance
>
> JL
>
>        [[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.