How to Copy the Exact Match From Data B to Data A in r

Question

Let's say I have two data frame A and B.

A

 products    price
   apple      3.0
   orange     2.5
   avocado    4.0
   banana     2.5
   blueberry  1.5

B

 products Color  price
 banana   Yellow  NA
 Apple    Red     NA
 Avocado  Green   NA
 Apricot  Yellow  NA

My question is what is the fastest way to grep the product prices from data A and save it in data B, so the result will be like this

B

products Color  price
  banana   Yellow  2.5
  Apple    Red     3.0
  Avocado  Green   4.0
  Apricot  Yellow  NA

Look into using `merge`. Not sure if that is the fastest way. — Tim Biegeleisen, Dec 14 '17 at 03:24
Anyway, in addition to `merge`, you can also look at `match` and see if that works for you. Something like `B$price <- A$price[match(tolower(B$products), tolower(A$products))]` perhaps. — A5C1D2H2I1M1N2O1R2T1, Dec 14 '17 at 03:28
thank you guys, I will try merge and match functions but I don't know how you can use left_join in this satiation? — Fouad Selmane, Dec 14 '17 at 03:32

score 1 · Answer 1 · answered Dec 14 '17 at 05:05

If the only difference between the products in B and A is the capitalization then you could use the following:

A = data.frame(products = c("apple", "orange", "avocado", "banana", "blueberry"),
           price = c(3.0, 2.5, 4.0, 2.5, 1.5))

B = data.frame(products = c("banana", "Apple", "Avocado", "Apricot"),
           color = c("Yellow", "Red", "Green", "Yellow"),
           price = c(NA, NA, NA, NA))

for (i in 1:nrow(B)) {
   B$price[i] =  A$price[match(tolower(B$products[i]), A$products)]
}

How to Copy the Exact Match From Data B to Data A in r

1 Answers1