In n3-initiative/n3r: Internal package for N3's oft-used functions

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

library(n3r)
library(dplyr)
library(tibble)

vlookup

This mimics Excel's vlookup() function - this is most handy when you just want to 'look up' one value from another dataframe. It's more intuitive than a join followed by dropping a bunch of columns.

Consider a master dataframe with these variables.

big <- mtcars %>% 
  rownames_to_column() %>% 
  rename(car = rowname)

big %>% 
  head()

Now suppose you only have 3 of these cars with mpg and cyl information. You want to look up the original dataframe and add a disp column.

small <- big %>% 
  head(3) %>% 
  select(car, mpg, cyl)
small

You would typically do this, but we're saddled with several superfluous columns.

small %>% 
  left_join(big) 

Instead, we can do

small %>% 
  mutate(displacement = vlookup(this = car, df = big, key = 'car', value = 'disp'))

This is very fast because it runs on base R and it is clean and intuitive!

n3-initiative/n3r documentation built on Dec. 26, 2019, 12:30 a.m.