Addresses bug where the number of missings in a row is not calcu…

[njtierney]

… properly, resolves 238 and 232. Solution also made prop_miss_case 3 times faster.

Description

Proportion of missings in a given case (row) had a line of code to protect against cases where there were all missings or some missings, but it had the logic reversed.

This was kind of hard to understand, so I wrote a new implementation using the rowSums(is.na(x)) pattern, which in my mind is easier to understand than using stats::complete.cases. It is also 3 times faster, which is a nice bonus.

library(naniar)

# This tests against
bad_air_quality <- tibble::tribble(
  ~Ozone, ~Solar.R, ~Wind, ~Temp, ~Month, ~Day,
  NA,      190,   7.4,    67,      5,    1,
  36,       NA,     8,    72,      5,    2,
  12,      149,    NA,    74,      5,    3,
  18,      313,  11.5,    NA,      5,    4,
  NA,       NA,  14.3,    56,     NA,    5,
  28,       NA,  14.9,    66,      5,   NA,
  NA,      190,   7.4,    67,      5,    1,
  36,       NA,     8,    72,      5,    2,
  12,      149,    NA,    74,      5,    3,
  18,      313,  11.5,    NA,      5,    4,
  NA,       NA,  14.3,    56,     NA,    5,
  28,       NA,  14.9,    66,      5,   NA
)

old <- function(x){
  
  temp <- x %>%
    # which rows are complete?
    stats::complete.cases() %>%
    mean()
  
  # Return 1 if temp is 1
  # Prevent error when all the rows contain a NA and then mean is 1
  # so (1 -1)*100 = 0, whereas function should return 1
  if (temp == 1) {
    return(0)
  }
  
  if (temp == 1) {
    # Return 0 if temp is 0
    # Prevent error when no row contains a NA and then mean is 0
    # so (1 -0)*1 = 1, whereas function should return 0.
    return(0)
  }
  
  return((1 - temp))
  
}

bm1 <- bench::mark(
  old = old(bad_air_quality),
  new = prop_miss_case(bad_air_quality)
)

bench:::autoplot.bench_mark(bm1)
#> Loading required namespace: tidyr

summary(bm1, relative = TRUE)
#> # A tibble: 2 x 6
#>   expression   min median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <dbl>  <dbl>     <dbl>     <dbl>    <dbl>
#> 1 old         3.19   3.20      1         2.21     1   
#> 2 new         1      1         3.36      1        1.18

^{Created on 2019-10-21 by the reprex package (v0.3.0)}

Related Issue

Closes #238 and #232

Example

naniar::prop_miss_case(tibble::tibble(x = NA))
#> [1] 1

^{Created on 2019-10-21 by the reprex package (v0.3.0)}

Tests

Yes - see

NEWS + DESCRIPTION

Yes - both.