I have a data frame like below:-
Var1 Var2 1 a a 2 a b 3 b a 4 b b I want an ID column containing values 1 and 2. How do I expand the above data frame so that the final data frame looks something like this?
Var1 Var2 ID 1 a a 1 2 a b 1 3 b a 1 4 b b 2 1 a a 2 2 a b 2 3 b a 2 4 b b 2 Ahh thanks to MKR, the issue is due to the package.
library(dplyr) df <- read.table(text = "Var1 Var2 1 a a 2 a b 3 b a 4 b b", header = TRUE, stringsAsFactors = FALSE) df %>% group_by(Var1, Var2) %>% expand(ID = 1:2) %>% arrange(ID) 3 Answers
Many options available to get the desired result. But perhaps OP seems to be keen on using tidyr::expand. A solution can be as:
library(dplyr) library(tidyr) df %>% group_by(Var1, Var2) %>% expand(ID = 1:2) %>% arrange(ID) # # A tibble: 8 x 3 # # Groups: Var1, Var2 [4] # Var1 Var2 ID # <chr> <chr> <int> # 1 a a 1 # 2 a b 1 # 3 b a 1 # 4 b b 1 # 5 a a 2 # 6 a b 2 # 7 b a 2 # 8 b b 2 Data:
df <- read.table(text = "Var1 Var2 1 a a 2 a b 3 b a 4 b b", header = TRUE, stringsAsFactors = FALSE) tidyr::expand did not work for me. However, tidyr::crossing worked like a charm.
The solution using crossing is:
library(tidyr) library(dplyr) df %>% crossing(ID = c(1:2)) %>% arrange(ID) # # A tibble: 8 x 3 # Var1 Var2 ID # <chr> <chr> <int> # 1 a a 1 # 2 a b 1 # 3 b a 1 # 4 b b 1 # 5 a a 2 # 6 a b 2 # 7 b a 2 # 8 b b 2 Data (gratefully copied from MKR <3):
df <- read.table(text = "Var1 Var2 1 a a 2 a b 3 b a 4 b b", header = TRUE, stringsAsFactors = FALSE) Here's something quite general:
library(dplyr) x <- head(cars,2) bind_rows(replicate(3,x,simplify = FALSE),.id="ID") # ID speed dist # 1 1 4 2 # 2 1 4 10 # 3 2 4 2 # 4 2 4 10 # 5 3 4 2 # 6 3 4 10 
