R help - Nov 2008 - Apply function

Hi all

I am manipulating a datafram which has 3 variables.Such as:

1  2  3
4  5  6
.  
.
.
200  210  300

I also has a row index: index=c(100,200,250..300)
I want to find the sums of first 100 rows, then the sum from row 101 to row
200, then row 201 to row 250... the each end row is indicated by the index.

Can I use the apply function to do that? or any other way?

Thanks

Ted


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Hi

r-help-bounces at r-project.org napsal dne 11.11.2008 06:59:55:
> 
> Hi all
> 
> I am manipulating a datafram which has 3 variables.Such as:
> 
> 1  2  3
> 4  5  6
> . 
> .
> .
> 200  210  300
> 
> I also has a row index: index=c(100,200,250..300)
> I want to find the sums of first 100 rows, then the sum from row 101 to 
row
> 200, then row 201 to row 250... the each end row is indicated by the 
index.

A little bit vague question, hence vague answer.

make a factor which has 3 values repeated 100 times (rep) and then use 
almost any of aggregation function ( e.g. tapply, by, aggregate) with sum 
function.

Regards
Petr
> 
> Can I use the apply function to do that? or any other way?
> 
> Thanks
> 
> Ted
> 
> 
> -- 
> View this message in context: http://www.nabble.com/Apply-function-
> tp20434042p20434042.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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