R: Why adding a new column to a data frame generates two columns?

Question

I want to add a column to a data frame that has a fix value, so based on this solution I do :

lessthan7.labels [, 'interval']=  c(rep( 'week', nrow(lessthan7)))

but then it creates two columns: "interval", "rep(\"week\", nrow(lessthan7))".

How to get rid of this extra column?

Answer 1

If you just want to assign a constant value to a new column in a data frame, you can just use the following list notation:

lessthan7$interval <- 'week'