Re: [R] count data with some conditions

From: Ted Harding <Ted.Harding_at_manchester.ac.uk>
Date: Sat, 01 Nov 2008 07:30:21 +0000 (GMT)


On 01-Nov-08 02:51:37, David Winsemius wrote:
> Do you want the count of remaining elements which are strictly
> greater than the first element?
>
> > length(which(a[1] < a[2:10]))
> [1] 4
>
> or perhaps a bit more deviously:
>
> > sum( a[1]<a[2:10]+0 ) #adding 0 to TRUE or FALSE creates 1 or 0.
> [1] 4

No need to be devious! Simply
  sum(a[1] < a[2:10])
# [1] 4
will do it. The reason is that when TRUE or FALSE are involved in an arithmetic operation (which sum() is), they are cast into 1 or 0.

Ted.

> On Oct 31, 2008, at 7:56 PM, sandsky wrote:

>> Hi there,
>> I have a data set:
>>
>> a=cbind(5,2,4,7,8,3,4,11,1,20)
>>
>> I want to count # of data, satistfying a[1]<a[2:10].
>> Anyone helps me solving this case?
>>
>> Thank you in advance,
>> Jin

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Date: 01-Nov-08                                       Time: 07:30:17
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