Function to update dataframe name stored in variable - r

Question

I am having to convert some dates to Character formats for a project I am working on, to make the code cleaner I wanted to write a function that you pass the name of the dataframe (and possibly the column name, though in this example it doesn't change so can be hard coded) to and it does the format for each, rather than having to repeat the full line for each dataframe I am formatting the column in.
Is this possible to do? I have done a lot of googling and can't seem to find an answer.
kpidataRM$Period <- format(kpidataRM$Period, "%b-%y")
kpidataAFM$Period <- format(kpidataAFM$Period, "%b-%y")
kpidataNATIONAL$Period <- format(kpidataNATIONAL$Period, "%b-%y")
kpidataHOD$Period <- format(kpidataHOD$Period, "%b-%y")

Answer 1

To answer your specific question, you could create a very simple function like this:
# Your function here takes as input the dataframe name (df) and formats the predefined column (Period)
new_function <- function(df){
df$Period <- format(df$Period, "%b-%y")
return(df)
}
and then run
df1 <- new_function(df1)
df2 <- new_function(df2)
for each of your dataframes (in your example df1 would be kpidataRM for instance). If you would like to include the column as a variable as well in your function you can write it like this:
# Your function here takes as input the dataframe name (df) and column name (col) and formats it.
new_function2 <- function(df, col){
df[[col]] <- format(df[[col]], "%b-%y")
return(df)
}
However, I would say though that this is not the best approach in this case, as you only seem to want to format a set of columns from a set of dataframes, in a specific way. What i would instead propose, exactly as Roland suggested, is to make a list of dataframes and iterate through each element. A simple example would look like this:
# Push all your dataframes in a list (dflist)
dflist <- list(df1,df2)
# Apply in this list a function that changes the column format (lapply)
dflist <- lapply(dflist, function(x){x[[Period]] <- format(x[[Period]], "%b-%y")})
Hope this works for you.