Matrix and Data Frame Max Column Values Filter, R

Language: Layout:

options(width=200)

myfile <- structure(list(mpg = c(18L, 15L, 18L, 16L, 17L, 15L, 14L, 14L, 
14L, 15L, 15L, 14L, 15L, 14L, 24L, 22L, 18L, 21L, 27L, 26L), 
    cylinders = c(8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 8L, 
    8L, 8L, 8L, 4L, 6L, 6L, 6L, 4L, 4L), displacement = c(307L, 
    350L, 318L, 304L, 302L, 429L, 454L, 440L, 455L, 390L, 383L, 
    340L, 400L, 455L, 113L, 198L, 199L, 200L, 97L, 97L), horsepower = c(130L, 
    165L, 150L, 150L, 140L, 198L, 220L, 215L, 225L, 190L, 170L, 
    160L, 150L, 225L, 95L, 95L, 97L, 85L, 88L, 46L), weight = c(3504L, 
    3693L, 3436L, 3433L, 3449L, 4341L, 4354L, 4312L, 4425L, 3850L, 
    3563L, 3609L, 3761L, 3086L, 2372L, 2833L, 2774L, 2587L, 2130L, 
    1835L), acceleration = c(12, 11.5, 11, 12, 10.5, 10, 9, 70.5, 
    10, 8.5, 10, 8, 9.5, 10, 15, 15.5, 15.5, 16, 14.5, 70.5), 
    year = c(70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L, 
    70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L, 70L), origin = c(1L, 
    1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 3L, 1L, 
    1L, 1L, 3L, 2L), name = c("chevrolet chevelle malibu", "buick skylark 320", 
    "plymouth satellite", "amc rebel sst", "ford torino", "ford galaxie 500", 
    "chevrolet impala", "plymouth fury iii", "pontiac catalina", 
    "amc ambassador dpl", "dodge challenger se", "plymouth 'cuda 340", 
    "chevrolet monte carlo", "buick estate wagon (sw)", "toyota corona mark ii", 
    "plymouth duster", "amc hornet", "ford maverick", "datsun pl510", 
    "volkswagen 1131 deluxe sedan")), row.names = c(NA, 20L), class = "data.frame")

#creating the matrix
num_cols <- c("mpg", "cylinders", "displacement", "horsepower",
              "weight", "acceleration", "year", "origin")

matrixAuto <- `dimnames<-`(as.matrix(myfile[,num_cols]), 
                           list(myfile$name, num_cols))

#matrixAuto

cat("\nMATRIX AGGREGATION---------------------------------------------------------------------------------------------------------\n")

max_vals_matrix <- apply(matrixAuto, 2, max)
max_vals_matrix

cat("\nMAX CYLINDERS\n")
mask <- matrixAuto[,"cylinders"] == max_vals_matrix["cylinders"]
matrixAuto[mask,]

cat("\nMAX ACCELERATION\n")
mask <- matrixAuto[,"acceleration"] == max_vals_matrix["acceleration"]
matrixAuto[mask,]

cat("\nMAX HORSEPOWER\n")
mask <- matrixAuto[,"horsepower"] == max_vals_matrix["horsepower"]
matrixAuto[mask,]

cat("\nMULTIPLE AGGREGATION\n")
agg_vals_matrix <- apply(matrixAuto, 2, function(col) c(max=max(col), min=min(col)))

mask <- matrixAuto[,"horsepower"] == agg_vals_matrix["min", "horsepower"]
matrixAuto[mask, drop=FALSE]   
row.names(matrixAuto[mask,,drop=FALSE])

cat("\n\n\nDATA FRAME AGGREGATION---------------------------------------------------------------------------------------------------------\n")
max_agg_df <- aggregate(cbind(mpg, cylinders, displacement, horsepower, weight,
                              acceleration, year, origin) ~ ., data=myfile[num_cols], FUN=max)
max_agg_df

cat("\nMAX CYLINDERS\n")
myfile[myfile$cylinder == max_agg_df$cylinder,]

cat("\nMAX ACCELERATION\n")
myfile[myfile$acceleration == max_agg_df$acceleration,]

cat("\nMAX HORSEPOWER\n")
myfile[myfile$horsepower == max_agg_df$horsepower,]

cat("\nMULTIPLE AGGREGATION\n")   
agg_raw <- aggregate(cbind(mpg, cylinders, displacement, horsepower, weight,
                          acceleration, year, origin) ~ ., data=myfile[num_cols], 
                     FUN=function(col) c(max=max(col), min=min(col)))
agg_df <- do.call(data.frame, agg_raw)
                        
myfile[myfile$horsepower == agg_df$horsepower.min,]
                        
myfile$name[myfile$horsepower == agg_df$horsepower.min]

[ + ] Show input
Absolute running time: 0.5 sec, cpu time: 0.96 sec, memory peak: 43 Mb, absolute service time: 0,78 sec