누락된 데이터, 누락된 데이터

R에서 결측치 다루기

Nicholas Tierney

Statistician

결측 데이터를 바라보는 또 다른 시각

name	time	value
robin	morning	358
robin	afternoon	534
robin	evening	100
sam	morning	139
sam	afternoon	177
blair	morning	963
blair	afternoon	962
blair	evening	929

name	afternoon	evening	morning
blair	962	929	963
robin	534	100	358
sam	177	NA	139

명시적 결측값과 암묵적 결측값

명시적: NA로 표시된 결측값
암묵적: 데이터에 나타나지 않지만 존재가 암시됨

암묵적 결측값을 명시적으로 변환

tetris %>%
  tidyr::complete(name, time)

# A tibble: 9 x 3
  name  time      value
  <fct> <fct>     <dbl>
1 blair afternoon   962
2 blair evening     929
3 blair morning     963
4 robin afternoon   534
5 robin evening     100
6 robin morning     358
7 sam   afternoon   177
8 sam   evening      NA
9 sam   morning     139

명시적 결측값 처리

name	time	value
robin	morning	936
NA	afternoon	635
NA	evening	438
sam	morning	208
NA	afternoon	92
NA	evening	79
blair	morning	969
NA	afternoon	918
NA	evening	954

name	time	value
robin	morning	936
robin	afternoon	635
robin	evening	438
sam	morning	208
sam	afternoon	92
sam	evening	79
blair	morning	969
blair	afternoon	918
blair	evening	954

명시적 결측값 처리

name	time	value
robin	morning	936
NA	afternoon	635
NA	evening	438
sam	morning	208
NA	afternoon	92
NA	evening	79
blair	morning	969
NA	afternoon	918
NA	evening	954

tetris %>%
  tidyr::fill(name)

# A tibble: 9 x 3
  name  time      value
  <chr> <chr>     <dbl>
1 robin morning     936
2 robin afternoon   635
3 robin evening     438
4 sam   morning     208
5 sam   afternoon    92
6 sam   evening      79
7 blair morning     969
8 blair afternoon   918
9 blair evening     954

주의 사항

tetris %>%
  tidyr::fill(name)

# A tibble: 9 x 3
  name  time      value
  <chr> <chr>     <dbl>
1 robin morning     936
2 robin afternoon   635
3 robin evening     438
4 sam   morning     208
5 sam   afternoon    92
6 sam   evening      79
7 blair morning     969
8 blair afternoon   918
9 blair evening     954

연습해 봅시다!

R에서 결측치 다루기