[R] How to combine two rows (in a dataframe) into a third row?

[Peter Alspach]

Tena koe Mark

?tapply

with the index argument some suitable substring of your ID column.

HTH ....

Peter Alspach 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Mark Na
> Sent: Friday, 10 July 2009 10:28 a.m.
> To: r-help at r-project.org
> Subject: [R] How to combine two rows (in a dataframe) into a 
> third row?
> 
> Dear R-helpers,
> 
> I have two rows in my dataframe:
> 
> ID    VALUE
> 1A    10
> 1B    15
> 
> and I would like to combine these two rows into a single 
> (new) row in my
> dataframe:
> 
> ID    VALUE
> 1    25
> 
> ...simply by specifying a new value for ID and summing the two VALUES.
> 
> I have been trying to do this with with rbind, but it's not working.
> 
> I'd appreciate any pointers.
> 
> Thanks, Mark Na
> 
> 	[[alternative HTML version deleted]]
> 
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> and provide commented, minimal, self-contained, reproducible code.
> 

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