R Iterierte über Spalten neue Spalten zu erstellen (mutieren oder Base R verwenden)

Question

ich Daten wie folge:

#create sample data frame 
df <- data.frame(red_alice_type1 = runif(10, 0, 10), 
        blue_alice_type1 = runif(10, 0, 10), 
        green_alice_type1 = runif(10, 0, 10), 
        red_bob_type1 = runif(10, 0, 10), 
        blue_bob_type1 = runif(10, 0, 10), 
        green_bob_type1 = runif(10, 0, 10), 
        red_alice_type2 = runif(10, 0, 10), 
        blue_alice_type2 = runif(10, 0, 10), 
        green_alice_type2 = runif(10, 0, 10), 
        red_bob_type2 = runif(10, 0, 10), 
        blue_bob_type2 = runif(10, 0, 10), 
        green_bob_type2 = runif(10, 0, 10)) 

Ich mag jedes Farbe-Namenspaar multiplizieren, um eine neue Spalte zu erstellen. z.B. blue_alice_type1 * blue_alice_type2 = blue_alice_product

ich versuche, über Spalten zu durchlaufen diese multiplation auszuführen, wie folgt:

#categories 
colors <- c('red', 'blue', 'green') 
names <- c('alice', 'bob') 

#Attempt 1: Mutate 
for (i in colors){ 
    for (j in names){ 
    df <- mutate_(df, 
        paste(i, j, 'product', sep = "_") = paste(i, j, 'type1', sep = "_") * 
        paste(i, j, 'type2', sep = "_")) 
    } 
} 

#Attempt 2: Base R 
for (i in colors){ 
    for (j in names){ 
    assign(paste0('df$', paste(i, j, 'product', sep = "_")), 
      eval(parse(text=paste0('df$', paste(i, j, 'type1', sep = "_")))) * 
       eval(parse(text=paste0('df$', paste(i, j, 'type2', sep = "_"))))) 
    } 
} 

Versuch 1 einen Fehler gibt. Versuch 2 läuft, aber erstellt keine neuen Spalten. Irgendeine Hilfe?

Answer 1

Ich würde die Spalten vom Typ geteilt und dann das Produkt berechnen:

#split on type and sort names 
type1 <- df[sort(grep('type1', names(df), value = TRUE))] 
type2 <- df[sort(grep('type2', names(df), value = TRUE))] 

#multiply (both data.frames have the same number of rows and columns) 
new_product <- type1 * type2 
#change names 
names(new_product) <- gsub('type1', 'product', names(new_product)) 
str(cbind(df, new_product)) 
#'data.frame': 10 obs. of 18 variables: 
# $ red_alice_type1 : num 9.46 4.024 1.953 9.411 0.373 ... 
# $ blue_alice_type1 : num 3.34 8.24 4.85 9.46 2.19 ... 
# $ green_alice_type1 : num 1.365 5.804 1.23 6.509 0.966 ... 
# $ red_bob_type1  : num 0.357 9.931 4.165 1.835 8.526 ... 
# $ blue_bob_type1  : num 1.488 1.532 2.848 0.907 0.914 ... 
# $ green_bob_type1 : num 8.275 8.482 9.895 0.657 1.457 ... 
# $ red_alice_type2 : num 2.188 7.536 4.391 0.202 5.482 ... 
# $ blue_alice_type2 : num 4.923 0.593 6.588 5.308 4.671 ... 
# $ green_alice_type2 : num 3.76 6.96 2.54 7.53 9.93 ... 
# $ red_bob_type2  : num 6.051 9.788 0.369 7.504 1.61 ... 
# $ blue_bob_type2  : num 7.55 9.56 1.1 7.89 6.48 ... 
# $ green_bob_type2 : num 2.36 2.94 7.57 2.62 6.74 ... 
# $ blue_alice_product : num 16.47 4.89 31.94 50.23 10.25 ... 
# $ blue_bob_product : num 11.24 14.64 3.14 7.15 5.92 ... 
# $ green_alice_product: num 5.13 40.38 3.13 49.05 9.59 ... 
# $ green_bob_product : num 19.56 24.94 74.9 1.72 9.82 ... 
# $ red_alice_product : num 20.7 30.32 8.58 1.9 2.05 ... 
# $ red_bob_product : num 2.16 97.2 1.54 13.77 13.73 ...