R - Issues while calling a user-defined function - r

Question

I have the following dataframe named "dataset"
> dataset
V1 V2 V3 V4 V5 V6 V7
1 A 29 27 0 14 21 163
2 W 70 40 93 63 44 1837
3 E 11 1 11 49 17 315
4 S 20 59 36 23 14 621
5 C 12 7 48 24 25 706
6 B 14 8 78 27 17 375
7 G 12 7 8 4 4 257
8 T 0 0 0 0 0 0
9 N 32 6 9 14 17 264
10 R 28 46 49 55 38 608
11 O 12 2 8 12 11 450
I have two helper functions as below
get_A <- function(p){
return(data.frame(Scorecard = p,
Results = dataset[nrow(dataset),(p+1)]))
} #Pulls the value from the last row for a given value of (p and offset by 1)
get_P <- function(p){
return(data.frame(Scorecard= p,
Results = dataset[p,ncol(dataset)]))
} #Pulls the value from the last column for a given value of p
I have the following dataframe on which I need to run the above helper functions. There will be NAs because I'm reading this "data_sub" dataframe from an excel file which can have unequal rows for the two columns.
> data_sub
Key_P Key_A
1 2 1
2 3 3
3 4 5
4 NA NA
When I call the helper functions, I get some strange results as shown below:
> get_P(data_sub[complete.cases(data_sub$Key_P),]$Key_P)
Scorecard Results
1 2 1837
2 3 315
3 4 621
> get_A(data_sub[complete.cases(data_sub$Key_A),]$Key_A)
Scorecard Results.V2 Results.V4 Results.V6
1 1 12 8 11
2 3 12 8 11
3 5 12 8 11
Warning message:
In data.frame(Scorecard = p, Results = dataset[nrow(dataset), (p + :
row names were found from a short variable and have been discarded
The call to the get_P() helper function is working the way I want. I'm getting the "Results" for each non-NA value in data_sub$Key_P as a dataframe.
But the call to the get_A() helper function is giving strange results and also a warning.I was expecting it to give a similar dataframe as given the call to get_P(). Why is this happening and how can I make get_A() to give the correct dataframe? Basically, the output of this should be
Scorecard Results
1 1 12
2 3 8
3 5 11
I found this link related to the warning but it's unhelpful in solving my issue.

Answer 1

The following works
get_P <- function(df, data_sub) {
data_sub <- data_sub[complete.cases(data_sub), ]
data.frame(
Scorecard = data_sub$Key_P,
Results = df[data_sub$Key_P, ncol(df)])
}
get_P(df, data_sub)
# Scorecard Results
#1 2 1837
#2 3 315
#3 4 621
get_A <- function(df, data_sub) {
data_sub <- data_sub[complete.cases(data_sub), ];
data.frame(
Scorecard = data_sub$Key_A,
Results = as.numeric(df[nrow(df), data_sub$Key_A + 1]))
}
get_A(df, data_sub)
# Scorecard Results
#1 1 12
#2 3 8
#3 5 11
To avoid the warning, we need to strip rownames with as.numeric in get_A.
Another tip: It's better coding practice to make get_P and get_A a function of both df and data_sub to avoid global variables.
Sample data
df <- read.table(text =
" V1 V2 V3 V4 V5 V6 V7
1 A 29 27 0 14 21 163
2 W 70 40 93 63 44 1837
3 E 11 1 11 49 17 315
4 S 20 59 36 23 14 621
5 C 12 7 48 24 25 706
6 B 14 8 78 27 17 375
7 G 12 7 8 4 4 257
8 T 0 0 0 0 0 0
9 N 32 6 9 14 17 264
10 R 28 46 49 55 38 608
11 O 12 2 8 12 11 450", header = T, row.names = 1)
data_sub <- read.table(text =
" Key_P Key_A
1 2 1
2 3 3
3 4 5
4 NA NA", header = T, row.names = 1)