Updating A Certain Column Values Within A User Defined Function In R - r

Question

I have the following piece of code to update a column in a dataframe in R with the median value. This works fine, but I would like to be able to call this as a function from other parts of the program, passing over other dataframes and columns.
medianVal <- median(df$column, na.rm = T)
df$column[is.na(df$column)] <- medianVal
The logic for the code I am attempting to use is Pass over the DataFrame and Column, Get the median Value, Update and return the dataframe
updateWithMedian <- function(DataFrame, Column)
{
medianValue <- median(Column, na.rm = T)
Column[is.na(DataFrame$Column)] <- medianValue
return(DataFrame)
}
DataFrame[[Column]] in the function helps me identify the column, but I am still struggling to update the NA values to the median.
For example, the code
DataFrame[[Column]][is.na(DataFrame$Column)] <- medianValue
dosent feel like the correct syntax.

Answer 1

You're mixing notations here. If you use quoted column names, you cannot use the dataframe$variable kind of notation. Try that (untested) solution:
updateWithMedian <- function(df, colname)
{
medianValue <- median(df[,colname], na.rm = T)
df[is.na(df[,colname]), colname] <- medianValue
return(df)
}

Answer 2

We can also do
library(dplyr)
library(zoo)
updateWithMedian <- function(df, colname) {
df %>%
mutate_at(vars(colname), na.aggregate, FUN = median)
}
updateWithMedian(df, "column")

Answer 3

Thanks, that has worked perfectly. Just a follow on question, if I wanted to update the column value with the value of a different column in the same dataframe, what would be the correct step for it?
I have tried the the code below but this replaces the NAs in Col1 with the Col2 Name, but its the value I need.
updateWithMedian <- function(df, colname1, colname2)
{
df[is.na(df[,colname1]), colname1] <- colname2
return(df)
}