We can always verify how character values relate:įor logical vectors FALSE can be read as 0 and TRUE as 1 which is the ascending order in which the values will be sorted. Also for character vectors the logic is simple: "a" is “smaller” than "b", so the ascending order goes from A to Z, with small coming before capital letters. For integer and double vectors (including Dates and date times, like POSIXct) this is pretty straightforward. Order() sorts the values from smallest to largest. Note hat the logic of ordering is the same for the most common data types. This makes it (relatively) easy to restore the old ordering: Now the rows are in the desired order, but note, that the row indices still correspond to the original indices. To actually order the rows according to this logic, we subset the ame by its rows according to the logic df: We can read this as: “The second row should come first, the third row should come second, and the first row should come last”. The output of order(dat$x) shows us the row numbers in which we would have to order our ame to make the values in dat$x run from smallest to highest. How does the above syntax work? Lets look at a three-column ame How different vector types are sorted and some more information about what exactly happens, when we call df can be found in the info box below. This is especially relevant for users coming from ‘dplyr’ or ‘data.table’.ĭplyr::arrange() always orders NAs last and doesn’t come with an option to change this behavior.ĭata.table::setorder() has an argument na.last, but (1) it can only be set TRUE or FALSE and (2) it defaults to the former which is the opposite of what MycarsĪ bit surprisingly na.last can also be set NA which will remove NAs from the vector or ame making it a combined filter and ordering operation:įor some users this behavior might not be very intuitive, which is why splitting ordering and filtering operations is preferable for code clarity. Setting na.last = FALSE sorts NAs to the top: Order() has an argument na.last which is set to TRUE by default and sorts NA to the bottom: Important to note is that, as default, NAs are sorted to bottom of the ame (read more about sorting NA values below). # order by two columns, first descending, second ascending: The ultimate guide to ordering rows in R | R-bloggers model cyl vs gear mpg disp
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