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Calculate sd and mean for many data frames in R

I have dataframes called bmw_1,bmw_2,...,bmw_9 and I want to calculate standard deviation and mean for each data frame but I don’t want to write:

mean(bmw_1)
mean(bmw_2)
mean(bmw_3)
...
mean(bmw_9)

How can I get this in a loop?

Solution

  • as mentioned in the comment, best way is to get the data frames into a list so you can apply a function over each.

    Get all dfs into a list by name pattern:

    ls_bmw <- mget(ls(pattern = "bmw_"))

    Then apply the mean.

    result <- lapply(ls_bmw, mean)

    Difficult to go much further without a data example, but to get the results alongside the data frame name use:

     names(ls_bmw)

    ... to get a vector of the df names and:

     unlist(result)

    ... to get a vector of the results. The order of names and results elements will match and you convert that into a single result dataframe.