I have the following dataframes:
df <- data.frame(x=c('a', 'b', 'c'), y=c(.1,.2,.3))
xev_values <- data.frame(a=.01, b=.02, c=.03)
How do I recode the character variables in the x column of df with the numeric values in xev_values so that I have a new dataframe?
new_df <- data.frame(xev=c(.01,.02,.03), y=c(.1,.2,.3))
I see how to do this "manually" with recode:
new_df <- data.frame(xev=recode(df$x, 'a'=.01, 'b'=.02, 'c'=.03), y=df$y)
We can convert xev_values to long-format, conduct a join, and then select the columns.
library(tidyverse)
df2 <- df %>%
left_join(xev_values %>% gather(x, xev), by = "x") %>%
select(xev, y)
df2
# xev y
# 1 0.01 0.1
# 2 0.02 0.2
# 3 0.03 0.3
If you have only one row in xev_values we can compare x column in df with that of names(xev_values) and extract the corresponding column value.
df$x <- unlist(xev_values[1, match(df$x, names(xev_values))])
df
# x y
#1 0.01 0.1
#2 0.02 0.2
#3 0.03 0.3
