In my data frame I am trying to sort the data in descending order. I am using the below line of code for sorting my data and it works as intended.

CNS25VOL <- CNS25VOL[order(-CNS25VOL$MATVOL22), ]

However if I refer to the same column by it's index number, the code throws an error

CNS25VOL <- CNS25VOL[order(-CNS25VOL[, 2]), ]

Error thrown is

Error in CNS25VOL[, 2] : incorrect number of dimensions

While I do have a solution to what I am intending to do, but issue I see is if all of a sudden name of my column changes the code won't work. I know that their position will stay same in the data frame.

How can we handle it.

CodePudding user response：

order(-CNS25VOL[, 2]) order here does expect a vector which you try to construct via the [] in CNS25VOL[, 2]. Normal dataframes will return a vector consisting only of the 2nd column. A tibble however will return a tibble with only one column.

You can reproduce the behaviour of normal data.frames with the drop = FALSE argument to [] as in

CNS25VOL[, 2, drop = TRUE]

Try to always be aware whether you are using a standard data.frame or a tibble or a data.table because they look very similar and are not in the details. Also see https://tibble.tidyverse.org/reference/subsetting.html

dplyr functions tend to give you a tibble back even if you fed them a classical data.frame.