[R] count element in column
(Ted Harding)
Ted.Harding at nessie.mcc.ac.uk
Wed Jan 5 18:43:03 CET 2005
On 05-Jan-05 Frederic renaud wrote:
> Hi,
> I 've a matrix n*1 (thus a column) and I would like to
> count the number of negative element inside.
> Can you help me?
> Thanks!
>
> eg:
> res[,1]= 1
> -3
> -1
>
> How obtain the number 2 (number of negative-element)?
If there is only one column, then either
sum(x<0)
or
sum(x[,1]<0)
If there is more than one column, then
sum(x[,1]<0)
sum(x[,2]<0)
...
does it for each column, one at a time, and
colSums(x<0)
does it for all the columns at once (but separately), while
sum(x<0)
does it for the whole matrix (without regard for columns).
Best wishes,
Ted.
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Date: 05-Jan-05 Time: 17:43:03
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