I have a simple function that takes two key parameters and returns a corresponding value from a tibble. The function works totally fine when I pass single values as arguments. But when applied to a tibble, the error wsa_m2 must be size 3 or 1, not 0 comes up.
require("tidyverse")
wsa <- tibble("trim" = c(4, 4, 4, 5, 5, 5, 6, 6, 6),
"draught" = c(7, 8, 9, 7, 8, 9, 7, 8, 9),
"wsa" = c(100, 200, 300, 400, 500, 600, 700, 800, 900))
data <- tibble("draught_m" = c(6, 5, 4), "trim_m" = c(9, 8, 7))
get_wsa <- function(draught_m, trim_m, wsa_tab) {
filter(wsa_tab, draught == draught_m &
trim == trim_m)$wsa
}
# works perfectly fine
a <- get_wsa(draught_m = 7, trim_m = 5, wsa_tab = wsa)
# error
data2 <- mutate(data, wsa_m2 = get_wsa(draught_m = data$draught_m,
trim_m = data$trim_m,
wsa_tab = wsa))
The Backtrace indicates that this seems to be a masking issue. I already tried solving the issue using enquo(), but didn't succeed... Any help is much appreciated!
Thanks in advance, Jonas
First of all, I think you have your columns interchanged in one of the dataframe. I am correcting data dataframe.
data <- tibble("trim_m" = c(6, 5, 4), "draught_m" = c(9, 8, 7))
But even after that it will not give the correct answer because when you run example by "hand" you only pass a single value but data$draught_m and data$trim_m have 3 values in. them. So you need to add rowwise to your code so that it executes for each row individually.
data2 <- data %>%
rowwise() %>%
mutate(wsa_m2 = get_wsa(draught_m = draught_m, trim_m, wsa_tab = wsa))
data2
# A tibble: 3 × 3
# Rowwise:
# trim_m draught_m wsa_m2
# <dbl> <dbl> <dbl>
#1 6 9 900
#2 5 8 500
#3 4 7 100
However, that can be inefficient for larger database and you should try using join instead.
data %>%
left_join(wsa, join_by(trim_m == trim, draught_m == draught))