Problem with map2 function

General
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#1

I'm trying to create a function that captures the amplitude of flight arrivals and departures. but getting this error: "non-numeric argument to binary operato". even though through the command class I discovered that arr and dep are numeric. I'm using nyclights13 data. Can you guys help?

library("nycflights13")
library("tidyverse")
library("tidylog")
library(magrittr)
library(purrr)


data <- flights %>% 
  group_by(dep_delay, arr_delay) %>% 
  summarise(n = n())

deptime_delay <- data$dep_delay

class(data$dep_delay)

arrtime_delay <- data$arr_delay

class(data$arr_delay)

fmp2 <- function(x, y) {
  result <- max("deptime_delay:", x, "arrtime_delay:", y) - min("deptime_delay:", x, "arrtime_delay:", y)
  return(result)
}

map2(deptime_delay, arrtime_delay , fmp2) %>% head(5)
#2

Hi @Shin1 ,

Really cool idea!

I'd like to take a stab at helping you out here, but let me know if I misunderstand your function fmp2.

What I believe is throwing the non-numeric to binary operator error is the presence of "deptime_delay:" and the other strings in the max() and min() functions. Now I could be wrong with that but I think those functions are only capable of handling numerics. I'm not sure what your goal is with those strings, whether you're looking to label your result or specify a column of data.

Here is a version of your code, minus the strings in the max and min functions:

# two example lists of numeric values to use
test_list_1 <- c(1, 2, 3, 4, 65)
test_list_2 <- c(12, 20, 100, 10, 9)

# version of your function that removes the character strings
test_fxn <- function(x, y) {
  testResult <- max(x, y) - min(x, y)
  return(testResult)
}

# running map2 over the lists with the test function
map2(test_list_1, test_list_2, test_fxn)

I hope this helps!

#3

Hi @Shin1 ,

Any luck getting your function to work?