Six variations on ranking functions, mimicking the ranking functions
described in SQL2003. They are currently implemented using the built in
rank function, and are provided mainly as a convenience when
converting between R and SQL. All ranking functions map smallest inputs
to smallest outputs. Use desc() to reverse the direction.
row_number(x) ntile(x = row_number(), n) min_rank(x) dense_rank(x) percent_rank(x) cume_dist(x)
| 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 | number of groups to split up into. |
row_number(): equivalent to rank(ties.method = "first")
min_rank(): equivalent to rank(ties.method = "min")
dense_rank(): like min_rank(), but with no gaps between
ranks
percent_rank(): a number between 0 and 1 computed by
rescaling min_rank to [0, 1]
cume_dist(): a cumulative distribution function. Proportion
of all values less than or equal to the current rank.
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.
#> [1] 5 1 4 2 3 NAmin_rank(x)#> [1] 5 1 4 2 2 NAdense_rank(x)#> [1] 4 1 3 2 2 NApercent_rank(x)#> [1] 1.00 0.00 0.75 0.25 0.25 NAcume_dist(x)#> [1] 1.0 0.2 0.8 0.6 0.6 NAntile(x, 2)#> [1] 2 1 2 1 1 NAntile(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#> 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