[R] How to list the all products' information of the latest month?

[arun]

dat1<- read.table(text="
Product    Price    Year_Month  PE
A                100        201012        -2
A                98          201101        -3
A                97          201102        -2.5
B                110        201101        -1
B                100        201102        -2
B                  90          201103        -4
",sep="",header=TRUE,stringsAsFactors=FALSE)
dat1[as.logical(with(dat1,ave(Year_Month,Product,FUN=function(x) x==max(x)))),]
#  Product Price Year_Month   PE
#3       A    97     201102 -2.5
#6       B    90     201103 -4.0
A.K.




----- Original Message -----
From: Tammy Ma <metal_licaling at live.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc: 
Sent: Friday, March 15, 2013 5:56 AM
Subject: [R] How to list the all products' information of the latest month?

Hi,

I have data frame like this:

Product     Price    Year_Month  PE
A                 100        201012         -2
A                 98           201101        -3
A                 97           201102        -2.5
B                 110         201101        -1
B                 100         201102        -2
B                  90          201103        -4


How can I achieve the following result using R:
Product     Price    Year_Month  PE
A                 97           201102        -2.5
B                  90          201103        -4

in other words, list the all products' information of the latest month?

Thanks for your help.

Kind regards,
Lingyi




                          
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