02-map.R

#Load packages
library(tidyverse)
library(here)

rm(list = ls()) #Clean out workspace

file_names <- list.files("data_example_1_2", pattern = ".txt",full.names = T)

#map applies a function to each element of a list or vector
map(file_names, toupper)

#map let's you define functions on the fly using ~, where '.x' serves as the item from the list/vector
map(file_names, ~toupper(.x)) #for .x in file_names, do ~ stuff

#Use map to get the full file path of each "short file" name
file_names_short <- list.files("data_example_1_2", pattern = ".txt",full.names = F)
map(file_names, ~here("data_example_1_2",.x))

#This isn't quite what we want. Map returns a list by default
ds <- map(file_names, ~ read_tsv(.x,  skip = 8, col_names = c("trial", "speed_actual", "speed_faster", "correct")))
ds <- bind_rows(ds) #This fixes it, but there's an easier way

#Map dfr is a variant of map that returns a dataframe by binding the result by rows
ds <- map_dfr(file_names, ~ read_tsv(.x,  skip = 8, col_names = c("trial", "speed_actual", "speed_faster", "correct")) %>% mutate(file = .x))

#lots of map variants to return data as different types
?map