R user-defined function called but not running - r

Question

I am new to R, and I am trying to create a user-defined function and run it inside a for loop. The function is defined in the same script before it is called. However, when the function is called, the code inside the function doesn't run. No syntax errors occur.
Here is the function definition:
placeInVector <- function(subjectID, morpho) {
if (morpho == "Alg") {
algVec <- c(algVec, subjectID)
}
else if (morpho == "Anem") {
anemVec <- c(anemVec, subjectID)
}
else if (morpho == "Barn") {
barnVec <- c(barnVec, subjectID)
}
else if (morpho == "Biv") {
bivVec <- c(bivVec, subjectID)
}
else if (morpho == "BrBryo") {
brbryoVec <- c(brbryoVec, subjectID)
}
else if (morpho == "ColTuni") {
coltuniVec <- c(coltuniVec, subjectID)
}
else if (morpho == "EnBryo") {
enbryoVec <- c(enbryoVec, subjectID)
}
else if (morpho == "Nothing") {
nothingVec <- c(nothingVec, subjectID)
}
else if (morpho == "SolTuni") {
soltuniVec <- c(soltuniVec, subjectID)
}
else if (morpho == "Spng") {
spngVec <- c(spngVec, subjectID)
}
else if (morpho == "TubeWm") {
tubewmVec <- c(tubewmVec, subjectID)
}
}
Here is where the function is called later on in the script:
for (subject in subjects$SubjectID) {
currentRow <- finalIDs %>%
filter(SubjectID == subject)
morphoID <- as.character(currentRow$FinalIDs1)
if (morphoID != "NONE") {
placeInVector(subject, morphoID)
}
}
Note: all of the vectors referenced in the function definition (algVec, anemVec, etc.) are defined as empty vectors.

Answer 1

As far as I understand, you are trying to add elements to vectors. Because I don't have a reproducible example, I will use my own. Here, add_to_vector adds elements to a and b:
a <- c(1,2)
b <- c("a","b")
add_to_vector <- function(vec, to_add){
vec <- c(vec, to_add)
return(vec)
}
a <- add_to_vector(a, 3)
b <- add_to_vector(b, "c")
Hopefully, this gives you an idea of how R works.
Output
> a
[1] 1 2 3
> b
[1] "a" "b" "c"