I have a dataframe:
ID value1 value2
1 f a
2 k p
3 c j
I want to replace values in column value1 with values from value2 and remove column value2. So desired result is:
ID value1
1 a
2 p
3 j
I need to do it with data.table. And i need to do it with function, not recreating dataframe from scratch.
library(data.table)
setDT(df)
df[, c("value1", "value2") := .(value2, NULL)]
Or with setnames()
df[, value1 := NULL]
setnames(df, "value2", "value1")
Data
df <- data.frame(
ID = 1:3, value1 = c("f", "k", "c"), value2 = c("a", "p", "j")
)
With data.table you can do :
library(data.table)
setDT(df)
df[, value1:=value2][, value2:=NULL]
You can do something like below
> setDT(df)[, .(ID, value1 = value2)]
ID value1
1: 1 a
2: 2 p
3: 3 j
Data
> dput(df)
structure(list(ID = 1:3, value1 = c("f", "k", "c"), value2 = c("a",
"p", "j")), class = "data.frame", row.names = c(NA, -3L))
Using dplyr
library(dplyr)
df %>%
select(ID, value1 = value2)
df <- structure(list(ID = 1:3, value1 = c("f", "k", "c"), value2 = c("a",
"p", "j")), class = "data.frame", row.names = c(NA, -3L))
