Six variations on ranking functions, mimicking the ranking functions described in SQL2003. They are currently implemented using the built in rank() function. All ranking functions map smallest inputs to smallest outputs. Use desc() to reverse the direction.

cume_dist(x)

dense_rank(x)

min_rank(x)

ntile(x = row_number(), n)

percent_rank(x)

row_number(x)

Arguments

x

A vector of values to rank. Missing values are left as is. If you want to treat them as the smallest or largest values, replace with Inf or -Inf before ranking.

n

integer(1). The number of groups to split up into.

Details

  • cume_dist(): a cumulative distribution function. Proportion of all values less than or equal to the current rank.

  • dense_rank(): like min_rank(), but with no gaps between ranks

  • min_rank(): equivalent to rank(ties.method = "min")

  • ntile(): a rough rank, which breaks the input vector into n buckets. The size of the buckets may differ by up to one, larger buckets have lower rank.

  • percent_rank(): a number between 0 and 1 computed by rescaling min_rank to [0, 1]

  • row_number(): equivalent to rank(ties.method = "first")

Examples

x <- c(5, 1, 3, 2, 2, NA) row_number(x)
#> [1] 5 1 4 2 3 NA
min_rank(x)
#> [1] 5 1 4 2 2 NA
dense_rank(x)
#> [1] 4 1 3 2 2 NA
percent_rank(x)
#> [1] 1.00 0.00 0.75 0.25 0.25 NA
cume_dist(x)
#> [1] 1.0 0.2 0.8 0.6 0.6 NA
ntile(x, 2)
#> [1] 2 1 2 1 1 NA
ntile(1:8, 3)
#> [1] 1 1 1 2 2 2 3 3
# row_number can be used with single table verbs without specifying x # (for data frames and databases that support windowing) mutate(mtcars, row_number() == 1L)
#> mpg cyl disp hp drat wt qsec vs am gear carb #> Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 #> Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 #> Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 #> Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 #> Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 #> Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 #> Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 #> Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 #> Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 #> Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 #> Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 #> Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3 #> Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3 #> Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3 #> Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4 #> Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4 #> Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4 #> Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 #> Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 #> Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 #> Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 #> Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2 #> AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 #> Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4 #> Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2 #> Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 #> Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 #> Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 #> Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4 #> Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 #> Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8 #> Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 #> row_number() == 1L #> Mazda RX4 TRUE #> Mazda RX4 Wag FALSE #> Datsun 710 FALSE #> Hornet 4 Drive FALSE #> Hornet Sportabout FALSE #> Valiant FALSE #> Duster 360 FALSE #> Merc 240D FALSE #> Merc 230 FALSE #> Merc 280 FALSE #> Merc 280C FALSE #> Merc 450SE FALSE #> Merc 450SL FALSE #> Merc 450SLC FALSE #> Cadillac Fleetwood FALSE #> Lincoln Continental FALSE #> Chrysler Imperial FALSE #> Fiat 128 FALSE #> Honda Civic FALSE #> Toyota Corolla FALSE #> Toyota Corona FALSE #> Dodge Challenger FALSE #> AMC Javelin FALSE #> Camaro Z28 FALSE #> Pontiac Firebird FALSE #> Fiat X1-9 FALSE #> Porsche 914-2 FALSE #> Lotus Europa FALSE #> Ford Pantera L FALSE #> Ferrari Dino FALSE #> Maserati Bora FALSE #> Volvo 142E FALSE
mtcars %>% filter(between(row_number(), 1, 10))
#> mpg cyl disp hp drat wt qsec vs am gear carb #> Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 #> Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 #> Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 #> Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 #> Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 #> Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 #> Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 #> Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 #> Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 #> Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4