Splitting based on multiple columns and then applying spread() in R

Question

I am trying to split my data into 3 parts based on 3 columns, and then want to spread the data for further processing. However, when I split using 2 columns, the code works. It doesn't work for 3 columns. This is built upon the discussion at How can I spread repeated measures of multiple variables into wide format?

Here's my data:

structure(list(Zone = c("East", "East", "East", "East", "East", 
"East", "East", "West", "West", "West", "West", "West", "West", 
"West"), Fiscal.Year = c(2016, 2016, 2016, 2016, 2016, 2016, 
2017, 2016, 2016, 2016, 2017, 2017, 2018, 2018), Transaction.ID = c(132, 
133, 134, 135, 136, 137, 171, 171, 172, 173, 175, 176, 177, 178
), L.Rev = c(3, 0, 0, 1, 0, 0, 2, 1, 1, 2, 2, 1, 2, 1), L.Qty = c(3, 
0, 0, 1, 0, 0, 1, 1, 1, 2, 2, 1, 2, 1), A.Rev = c(0, 0, 0, 1, 
1, 1, 0, 0, 0, 0, 0, 1, 0, 0), A.Qty = c(0, 0, 0, 2, 2, 3, 0, 
0, 0, 0, 0, 3, 0, 0), I.Rev = c(4, 4, 4, 0, 1, 0, 3, 0, 0, 0, 
1, 0, 1, 1), I.Qty = c(2, 2, 2, 0, 1, 0, 3, 0, 0, 0, 1, 0, 1, 
1)), .Names = c("Zone", "Fiscal.Year", "Transaction.ID", "L.Rev", 
"L.Qty", "A.Rev", "A.Qty", "I.Rev", "I.Qty"), row.names = c(NA, 
14L), class = "data.frame")

Here's the code that works:

Input_File %>%
gather(Rev_Qty,Value, L.Rev:I.Qty)  %>%
separate(Rev_Qty, into=c("L.A","Rev.Qty")) %>% 
split(.,list(.$Zone,.$Rev.Qty)) %>%  
#Ideally, I want three-way split--i.e. Fiscal.Year, Zone and Rev.Qty
purrr::map(~unite(.,LAType.Rev.Qty, L.A, Rev.Qty, sep = ".")) %>% 
purrr::map(~spread_(.,key_col = "LAType.Rev.Qty", value_col = "Value"))

This works nicely--i.e. I get a list of length 4 that I can use for further processing.

However, the following code doesn't work when I apply three-way split based on Rev.Qty; Zone and Fiscal.Year.

Input_File %>%
gather(Rev_Qty,Value, L.Rev:I.Qty)  %>%
separate(Rev_Qty, into=c("L.A","Rev.Qty")) %>% 
#Now split the data based on zone, Rev vs. Qty and year--DOESN'T WORK
split(.,list(.$Zone,.$Rev.Qty,.$Fiscal.Year)) %>%
purrr::map(~unite(.,LAType.Rev.Qty, L.A, Rev.Qty, sep = ".")) %>% 
purrr::map(~spread_(.,key_col = "LAType.Rev.Qty", value_col = "Value"))

I get the following error:

Error in enc2utf8(col_names(col_labels, sep = sep)) : 
  argumemt is not a character vector

Upon debugging, I found that the code executes well until the unite(). It breaks as soon as I call spread_().

Expected Output: If we run the code until unite(), we will see that we will get a list of length 12. Expected output would be this list after the application of spread on LAType.Rev.Qty and Value columns. I hope this clarifies the expected output.

Can someone please help me what's going on? I am a beginner, and I've no clue what's happening.

Answer 1

We need drop=TRUE in split to remove the combinations that do not exist in the dataset

Input_File %>%
      gather(Rev_Qty,Value, L.Rev:I.Qty)  %>%
      separate(Rev_Qty, into=c("L.A","Rev.Qty")) %>% 
      split(.,list(.$Zone,.$Rev.Qty,.$Fiscal.Year), drop = TRUE) %>%
      purrr::map(~unite(.,LAType.Rev.Qty, L.A, Rev.Qty, sep = ".")) %>% 
      purrr::map(~spread_(.,key_col = "LAType.Rev.Qty", value_col = "Value"))