Reputation: 1906
I have a df with a number of columns.
I want to multiply each of the column using a fixed constant.
I am looking for the best possible strategy to achieve this using purrr
(I am still trying to get my head around lamp
etc etc)
library(tidyverse)
library(lubridate)
df1 <- data.frame(
date = ymd(c("2019-02-01", "2019-02-02", "2019-02-03", "2019-02-04",
"2019-02-05")),
x = c(1, 2, 3, 4, 5),
y = c(2, 3, 4, 5, 6),
z = c(3, 4, 5, 6, 7)
)
The constants to multiply each of the column is as follows:
c(10, 20, 30)
This is the output I expect:
data.frame(
date = ymd(c("2019-02-01", "2019-02-02", "2019-02-03", "2019-02-04",
"2019-02-05")),
x = c(10, 20, 30, 40, 50),
y = c(40, 60, 80, 100, 120),
z = c(90, 120, 150, 180, 210)
)
Upvotes: 2
Views: 62
Reputation: 39154
We can use map2
from purrr
(part of the tidyverse
) to achieve this.
df1[2:4] <- map2(df1[2:4], c(10, 20, 30), ~.x * .y)
df1
# date x y z
# 1 2019-02-01 10 40 90
# 2 2019-02-02 20 60 120
# 3 2019-02-03 30 80 150
# 4 2019-02-04 40 100 180
# 5 2019-02-05 50 120 210
The base R equivalent is mapply
.
df1[2:4] <- mapply(FUN = function(x, y) x * y, df1[2:4], c(10, 20, 30), SIMPLIFY = FALSE)
Upvotes: 4