[R] Extract from data.frame

[Mark Sharp]

Nico, 

I expect there are many better ways to do this, but this does work:
max_row <- (1:nrow(df))[which.max(df$Amount)]
mean(df$Amount[max_row + c(-1, 0, 1)])

> max_row <- (1:nrow(df))[which.max(df$Amount)]
> mean(df$Amount[max_row + c(-1, 0, 1)])
[1] 151.6667

R. Mark Sharp, Ph.D.
Director of Primate Records Database
Southwest National Primate Research Center
Texas Biomedical Research Institute
P.O. Box 760549
San Antonio, TX 78245-0549
Telephone: (210)258-9476
e-mail: msharp at TxBiomed.org




> On Sep 21, 2015, at 9:52 AM, Nico Gutierrez <nico.gutierrezo at gmail.com> wrote:
> 
> Hi All,
> 
> I need to do the following operation from data.frame:
> 
> df <- data.frame(Year = c("2001", "2002", "2003", "2004", "2005", "2006",
> "2007"), Amount = c(150, 120, 175, 160, 120, 105, 135))
> df[which.max(df$Amount),]  #to extract row with max Amount.
> 
> Now I need to do 3 years average around the max Amount value (ie:
> mean(120,175,160))
> 
> Thanks!
> N
> 
> 	[[alternative HTML version deleted]]
> 
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