na - How to leave out rows with missing values when total no. of values crosses a given value in R -
i have dataset contains 45% of missing values:
i remove rows has na's values given period. example, if there rows continuously has missing values ,for hour or more 50 values missing continuously , want remove rows alone. , don't want leave rows missing values less 15 or 25.
in short, 1) don't want remove rows has got na value's. 2) want remove rows continuously has na values in column
example data: pic
discard columnwise contiguous nas
try this, uses rle(is.na...)) determine runs of nas. if > num_runs discarded (data @ bottom)
myfun <- function(x, num_runs) { # x vector column of df require(dplyr) runs <- cumsum(rle(is.na(x))$lengths) vals <- rle(is.na(x))$values start <- dplyr::lag(runs)+1 start <- replace(start, is.na(start), 1) m <- rbind(start[vals], runs[vals]) seqruns <- apply(m, 2, function(x) if ((x[2]-x[1]+1) > num_runs) { seq(x[1],x[2]) }) ans <- unlist(seqruns) return(ans) } library(purrr) library(dplyr) num_runs <- 4 discard <- unlist(map(1:ncol(df), ~myfun(df[,.x, num_runs]))) df[-discard,]
output
mpg cyl disp hp drat wt qsec vs 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 na 1 hornet sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 na 2 valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 na 1 duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 na 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 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 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
discard rowwise contiguous nas
try this, uses rle(is.na...))
determine runs of na
s. if any
> num_runs
discarded (data @ bottom)
library(purrr) num_runs <- 1 # number of contiguous nas keep <- map_lgl(1:nrow(df), ~!any(rle(is.na(unlist(df[.x,])))$lengths[rle(is.na(unlist(df[.x,])))$values] > num_runs)) df[keep,]
output
mpg cyl disp hp drat wt qsec vs 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 na 1 hornet sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 na 2 valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 na 1 duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 na 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 cadillac fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 na 4 lincoln continental 10.4 8 460.0 215 na 5.424 17.82 0 0 na 4 chrysler imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 na 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 na 1 dodge challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 na 2 amc javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 na 2 camaro z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 na 4 pontiac firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 na 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
data
library(dplyr) df <- mtcars %>% replace(.==3, na)
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