Previous marking nullified while using ifelse condition in R - r

Question

Here is my data -
library(data.table)
basefile2 = data.table(States = c("California","California", "California", "Texas","Texas","Texas", "Ohio", "Ohio", "Ohio"),
Cities = c("LA", "California City", "San Fran", "Houston", "Dallas", "Austin", "Columbus", "Cleaveland", "Wooster"))
And here is my code -
Market = function(state, city){
if (missing(state)) stop("Enter State",
call. = FALSE)
if (missing(city)) stop("Enter City(ies)",
call. = FALSE)
basefile2 <<- basefile2[, "Consideration" := ifelse(States == state & Cities %in% city, "Y",
ifelse("Consideration" %in% colnames(basefile) & "Consideration" == "Y", "Y", "N"))]
}
Market(state = "California",
city = c("LA", "California City"))
Market(state = "Texas",
city = c("Dallas", "Austin"))
The previous marking in the consideration column when state was California is getting nullified. Yes, I need to input different states in separate functions to due to certain input constraints
Here is my output
States Cities Consideration
1: California LA N
2: California California City N
3: California San Fran N
4: Texas Houston N
5: Texas Dallas Y
6: Texas Austin Y
7: Ohio Columbus N
8: Ohio Cleaveland N
9: Ohio Wooster N
Where as, the output I need is the consideration column must have "Y" in the California City, LA, Austin & Dallas.

Answer 1

One option is to add the "Consideration" column to the data.table at the start, and then use that as a condition to update within the function so that previous updates are not replaced.
library(data.table)
basefile2 <- data.table(...) # as you had
basefile2[, Consideration := "N"] # initialize the column
Market <- function(state, city){
basefile2 <<- basefile2[Consideration=="N", # Only update if this is "N"
"Consideration" := ifelse(States == state & Cities %in% city, "Y", "N")]
}
Or maybe like this:
Market <- function(state, city){
basefile2 <<- basefile2[States == state & Cities %in% city, Consideration := "Y"]
}
Market(state = "California", city = c("LA", "California City"))
Market(state = "Texas", city = c("Dallas", "Austin"))
basefile2
States Cities Consideration
1: California LA Y
2: California California City Y
3: California San Fran N
4: Texas Houston N
5: Texas Dallas Y
6: Texas Austin Y
7: Ohio Columbus N
8: Ohio Cleaveland N
9: Ohio Wooster N