Smaller example of problem with min_rank

dplyr-minrank-small.R

library(dplyr)  # using 0.1.3


# generate some test data
set.seed(101)
test <- tbl_df(data.frame(ID=sample(1:5, 50, replace=TRUE), X=sample(101:105, 50, replace=TRUE)))
test <- arrange(test, ID)
people <- group_by(test, ID)


# let's take a look at the data
print(people)
#    ID   X
# 1   1 103
# 2   1 105
# 3   1 101
# 4   1 104
# 5   1 105
# 6   1 101
# 7   1 102
# 8   1 101
# 9   2 101
# 10  2 103
# 11  2 104
# 12  2 103
# 13  2 102
# 14  2 103
# 15  2 102
# 16  2 104
# 17  2 102
# 18  2 101
# 19  2 102
# 20  2 105
# 21  3 104
# 22  3 103
# 23  3 105
# 24  3 104
# 25  3 105
# 26  3 104
# 27  3 104
# 28  3 101
# 29  3 104
# 30  3 105
# 31  4 104
# 32  4 104
# 33  4 104
# 34  4 105
# 35  4 104
# 36  4 102
# 37  4 105
# 38  4 102
# 39  4 105
# 40  4 104
# 41  4 101
# 42  5 105
# 43  5 105
# 44  5 101
# 45  5 105
# 46  5 105
# 47  5 105
# 48  5 103
# 49  5 101
# 50  5 102


# use row_number: results look correct
mutate(people, new=row_number(desc(X))) %.% arrange(ID, new)
#    ID   X new
# 1   1 105   1
# 2   1 105   2
# 3   1 104   3
# 4   1 103   4
# 5   1 102   5
# 6   1 101   6
# 7   1 101   7
# 8   1 101   8
# 9   2 105   1
# 10  2 104   2
# 11  2 104   3
# 12  2 103   4
# 13  2 103   5
# 14  2 103   6
# 15  2 102   7
# 16  2 102   8
# 17  2 102   9
# 18  2 102  10
# 19  2 101  11
# 20  2 101  12
# 21  3 105   1
# 22  3 105   2
# 23  3 105   3
# 24  3 104   4
# 25  3 104   5
# 26  3 104   6
# 27  3 104   7
# 28  3 104   8
# 29  3 103   9
# 30  3 101  10
# 31  4 105   1
# 32  4 105   2
# 33  4 105   3
# 34  4 104   4
# 35  4 104   5
# 36  4 104   6
# 37  4 104   7
# 38  4 104   8
# 39  4 102   9
# 40  4 102  10
# 41  4 101  11
# 42  5 105   1
# 43  5 105   2
# 44  5 105   3
# 45  5 105   4
# 46  5 105   5
# 47  5 103   6
# 48  5 102   7
# 49  5 101   8
# 50  5 101   9


# use min_rank: works properly for ID=1, but not for other IDs
mutate(people, new=min_rank(desc(X))) %.% arrange(ID, new)
#    ID   X new
# 1   1 105   1
# 2   1 105   1
# 3   1 104   3
# 4   1 103   4
# 5   1 102   5
# 6   1 101   6
# 7   1 101   6
# 8   1 101   6
# 9   2 103   1
# 10  2 102   1
# 11  2 103   3
# 12  2 102   3
# 13  2 101   5
# 14  2 101   5
# 15  2 105   5
# 16  2 102   8
# 17  2 104   9
# 18  2 103   9
# 19  2 104   9
# 20  2 102   9
# 21  3 103   1
# 22  3 105   1
# 23  3 104   3
# 24  3 104   4
# 25  3 105   4
# 26  3 104   6
# 27  3 105   7
# 28  3 104   7
# 29  3 101   7
# 30  3 104   7
# 31  4 104   1
# 32  4 104   1
# 33  4 105   3
# 34  4 101   3
# 35  4 104   5
# 36  4 104   5
# 37  4 105   7
# 38  4 104   8
# 39  4 102   8
# 40  4 102   8
# 41  4 105   8
# 42  5 105   1
# 43  5 105   1
# 44  5 105   3
# 45  5 105   4
# 46  5 103   5
# 47  5 101   6
# 48  5 105   6
# 49  5 101   6
# 50  5 102   6