R help - Jan 2014 - Find the maximum value of a column in a matrix

HI,
The input and output dataset looks different (typo?) in "profit"
column.
dat1 <- read.table(text="Place? Prod? Loctn? profit
S1???? P1???? Loc1??? 55
S1???? P2???? Loc1?? 80
S1???? P3???? Loc2?? 70
S1???? P1???? Loc2?? 60
S2???? P2???? Loc1?? 30??? 
S2???? P3???? Loc1?? 40
S2???? P1???? Loc1?? 15
S2???? P2???? Loc2??
20",sep="",header=TRUE,stringsAsFactors=FALSE)

dat2 <- within(dat1,solution<-(ave(profit,Loctn,Place,FUN=max)==profit)*1)
dat2$solution
[1] 0 1 1 0 0 1 0 1 ##Also, based on the question, the last entry seems to be
1??
A.K.




Hi All, 

I have following matrix: 

Place ?Prod ?Loctn ?profit 
S1 ? ? P1 ? ? loc1 ? ?55 
S1 ? ? P2 ? ? Loc1 ? 80 
S1 ? ? P3 ? ? Loc2 ? 70 
S1 ? ? P1 ? ? Loc2 ? 90 
S2 ? ? P2 ? ? Loc1 ? 30 ? ? 
S2 ? ? P3 ? ? Loc1 ? 40 
S2 ? ? P1 ? ? Loc2 ? 15 
S2 ? ? P2 ? ? Loc2 ? 20 

I want for each place, which product is giving maximum profit at each location
and output should be in following form

Place ?Prod ?Loctn ?profit ?solution 
S1 ? ? P1 ? ? loc1 ? ?55 ? ? ? ? ? 0 
S1 ? ? P2 ? ? Loc1 ? 80 ? ? ? ? ? 1 
S1 ? ? P3 ? ? Loc2 ? 70 ? ? ? ? ? 1 ? ? ? ? ? ? 
S1 ? ? P1 ? ? Loc2 ? 60 ? ? ? ? ? 0 
S2 ? ? P2 ? ? Loc1 ? 30 ? ? ? ? ? 0 ? ? 
S2 ? ? P3 ? ? Loc1 ? 40 ? ? ? ? ? 1 ? ? ? ? ? 
S2 ? ? P1 ? ? Loc1 ? 15 ? ? ? ? ? 0 
S2 ? ? P2 ? ? Loc2 ? 20 ? ? ? ? ? 0 

Thanks in advance