I'm trying to create a loop that renames some variables in a list of data frames and sorts the rows using a variable. I have tried with this code (_var1, _var2 and var3 are present in each dataframe):

dfnames <- c("df1", "df2", "df3", "df4", "df5", "df5", "df6")

for (cur.dfname in dfnames) {   
  cur.df <- get(cur.dfname)
  cur.df <- rename(cur.df, var1 = "_var1", var2 = "_var2")
  cur.df <- arrange(cur.df, var3, desc(var1))
}

This code does not appear to work and no error message is generated.

CodePudding user response：

The object cur.df is only known inside the (scope of the) loop. To change the dataframe(s) outside the loop, you can assign it to the parent environment like:

for (cur.dfname in dfnames) {   
  cur.df <- get(cur.dfname)
  cur.df <- rename(cur.df, 'var1' = '_var1')
  cur.df <- arrange(cur.df, 'var1')
  ## manipulate objects beyond the loop scope:
  assign(cur.dfname, cur.df, envir = parent.frame(1))
}

Note that such scope breaking is considered bad practice.