Is there an equivalent R function to Stata 'order' command?

Question

\'order\' in R seems like \'sort\' in Stata. Here\'s a dataset for example (only variable names listed):

v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13 v14 v15 v16 v17 v

Answer 1

This should give you the same file:

#snip
gtinfo <- rbind(tweetinfo, noretweetinfo)
gtinfo$deleted=""
retweetinfo <- transform(retweetinfo, reTweetId="", reUserId="")
gtinfo <- rbind(gtinfo, retweetinfo)
gtinfo <-gtinfo[,c(1:16,18,17)]
#snip

It is possible to implement a function like Strata's order function in R, but I don't think there is much demand for that.

Answer 2

The package dplyr and the function dplyr::relocate, a new verb introduced in dplyr 1.0.0, does exactly what you are looking for.

library(dplyr)

data %>% relocate(v17, v18, .before = v13)

data %>% relocate(v6, v16, .after = last_col())

data %>% relocate(age, .after = gender)

Answer 3

Because I'm procrastinating and experimenting with different things, here's a function that I whipped up. Ultimately, it depends on append:

moveme <- function(invec, movecommand) {
  movecommand <- lapply(strsplit(strsplit(movecommand, ";")[[1]], ",|\\s+"), 
                        function(x) x[x != ""])
  movelist <- lapply(movecommand, function(x) {
    Where <- x[which(x %in% c("before", "after", "first", "last")):length(x)]
    ToMove <- setdiff(x, Where)
    list(ToMove, Where)
  })
  myVec <- invec
  for (i in seq_along(movelist)) {
    temp <- setdiff(myVec, movelist[[i]][[1]])
    A <- movelist[[i]][[2]][1]
    if (A %in% c("before", "after")) {
      ba <- movelist[[i]][[2]][2]
      if (A == "before") {
        after <- match(ba, temp)-1
      } else if (A == "after") {
        after <- match(ba, temp)
      }    
    } else if (A == "first") {
      after <- 0
    } else if (A == "last") {
      after <- length(myVec)
    }
    myVec <- append(temp, values = movelist[[i]][[1]], after = after)
  }
  myVec
}

Here's some sample data representing the names of your dataset:

x <- paste0("v", 1:18)

Imagine now that we wanted "v17" and "v18" before "v3", "v6" and "v16" at the end, and "v5" at the beginning:

moveme(x, "v17, v18 before v3; v6, v16 last; v5 first")
#  [1] "v5"  "v1"  "v2"  "v17" "v18" "v3"  "v4"  "v7"  "v8"  "v9"  "v10" "v11" "v12"
# [14] "v13" "v14" "v15" "v6"  "v16"

So, the obvious usage would be, for a data.frame named "df":

df[moveme(names(df), "how you want to move the columns")]

And, for a data.table named "DT" (which, as @mnel points out, would be more memory efficient):

setcolorder(DT, moveme(names(DT), "how you want to move the columns"))

---

Note that compound moves are specified by semicolons.

The recognized moves are:

• before (move the specified columns to before another named column)
• after (move the specified columns to after another named column)
• first (move the specified columns to the first position)
• last (move the specified columns to the last position)

Answer 4

It is very unclear what you would like to do, but your first sentence makes me assume you would like to sort dataset.

Actually, there is a built-in order function, which returns the indices of the ordered sequence. Are you searching this?

> x <- c(3,2,1)

> order(x)
[1] 3 2 1

> x[order(x)]
[1] 1 2 3

Answer 5

I get your problem. I now have code to offer:

move <- function(data,variable,before) {
  m <- data[variable]
  r <- data[names(data)!=variable]
  i <- match(before,names(data))
  pre <- r[1:i-1]
  post <- r[i:length(names(r))]
  cbind(pre,m,post)
}

# Example.
library(MASS)
data(painters)
str(painters)

# Move 'Expression' variable before 'Drawing' variable.
new <- move(painters,"Expression","Drawing")
View(new)

Answer 6

You could write your own function that does this.

The following will give you the new order for your column names using similar syntax to stata

• where is a named list with 4 possibilities

  • list(last = T)
  • list(first = T)
  • list(before = x) where x is the variable name in question
  • list(after = x) where x is the variable name in question

• sorted = T will sort var_list lexicographically (a combination of alphabetic and sequential from the stata command

The function works on the names only, (once you pass a data.frame object as data, and returns a reordered list of names

eg

stata.order <- function(var_list, where, sorted = F, data) {
    all_names = names(data)
    # are all the variable names in
    check <- var_list %in% all_names
    if (any(!check)) {
        stop("Not all variables in var_list exist within  data")
    }
    if (names(where) == "before") {
        if (!(where %in% all_names)) {
            stop("before variable not in the data set")
        }
    }
    if (names(where) == "after") {
        if (!(where %in% all_names)) {
            stop("after variable not in the data set")
        }
    }

    if (sorted) {
        var_list <- sort(var_list)
    }
    where_in <- which(all_names %in% var_list)
    full_list <- seq_along(data)
    others <- full_list[-c(where_in)]

    .nwhere <- names(where)
    if (!(.nwhere %in% c("last", "first", "before", "after"))) {
        stop("where must be a list of a named element first, last, before or after")
    }

    do_what <- switch(names(where), last = length(others), first = 0, before = which(all_names[others] == 
        where) - 1, after = which(all_names[others] == where))

    new_order <- append(others, where_in, do_what)
    return(all_names[new_order])
}

tmp <- as.data.frame(matrix(1:100, ncol = 10))

stata.order(var_list = c("V2", "V5"), where = list(last = T), data = tmp)

##  [1] "V1"  "V3"  "V4"  "V6"  "V7"  "V8"  "V9"  "V10" "V2"  "V5" 

stata.order(var_list = c("V2", "V5"), where = list(first = T), data = tmp)

##  [1] "V2"  "V5"  "V1"  "V3"  "V4"  "V6"  "V7"  "V8"  "V9"  "V10"

stata.order(var_list = c("V2", "V5"), where = list(before = "V6"), data = tmp)

##  [1] "V1"  "V3"  "V4"  "V2"  "V5"  "V6"  "V7"  "V8"  "V9"  "V10"

stata.order(var_list = c("V2", "V5"), where = list(after = "V4"), data = tmp)

##  [1] "V1"  "V3"  "V4"  "V2"  "V5"  "V6"  "V7"  "V8"  "V9"  "V10"

# throws an error
stata.order(var_list = c("V2", "V5"), where = list(before = "v11"), data = tmp)

## Error: before variable not in the data set

if you want to do the reordering memory-efficiently (by reference, without copying) use data.table

DT <- data.table(tmp)
# sets by reference, no copying
setcolorder(DT, stata.order(var_list = c("V2", "V5"), where = list(after = "V4"), 
    data = DT))

DT

##     V1 V3 V4 V2 V5 V6 V7 V8 V9 V10
##  1:  1 21 31 11 41 51 61 71 81  91
##  2:  2 22 32 12 42 52 62 72 82  92
##  3:  3 23 33 13 43 53 63 73 83  93
##  4:  4 24 34 14 44 54 64 74 84  94
##  5:  5 25 35 15 45 55 65 75 85  95
##  6:  6 26 36 16 46 56 66 76 86  96
##  7:  7 27 37 17 47 57 67 77 87  97
##  8:  8 28 38 18 48 58 68 78 88  98
##  9:  9 29 39 19 49 59 69 79 89  99
## 10: 10 30 40 20 50 60 70 80 90 100