그룹화된 mutate

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James Chapman

Curriculum Manager, DataCamp

selected-names-plot

복습: group_by()와 summarize()

babynames %>%
  group_by(year) %>%
  summarize(year_total = sum(number))

# A tibble: 28 x 2
    year year_total
   <dbl>      <int>
 1  1880     201478
 2  1885     240822
 3  1890     301352
 4  1895     350934
 5  1900     450148
 6  1905     423875
 7  1910     590607
 8  1915    1830351
 9  1920    2259494
10  1925    2330750
# … with 18 more rows

group_by()와 mutate() 결합

babynames %>%
  group_by(year) %>%
  mutate(year_total = sum(number))

# A tibble: 332,595 x 4
# Groups:   year [28]
    year name    number year_total
   <dbl> <chr>    <int>      <int>
 1  1880 Aaron      102     201478
 2  1880 Ab           5     201478
 3  1880 Abbie       71     201478
 4  1880 Abbott       5     201478
 5  1880 Abby         6     201478
 6  1880 Abe         50     201478
 7  1880 Abel         9     201478
 8  1880 Abigail     12     201478
 9  1880 Abner       27     201478
10  1880 Abraham     81     201478
# … with 332,585 more rows

ungroup()

babynames %>%
  group_by(year) %>%
  mutate(year_total = sum(number)) %>%
  ungroup()

# A tibble: 332,595 x 4
    year name    number year_total
   <dbl> <chr>    <int>      <int>
 1  1880 Aaron      102     201478
 2  1880 Ab           5     201478
 3  1880 Abbie       71     201478
 4  1880 Abbott       5     201478
 5  1880 Abby         6     201478
 6  1880 Abe         50     201478
 7  1880 Abel         9     201478
 8  1880 Abigail     12     201478
 9  1880 Abner       27     201478
10  1880 Abraham     81     201478
# … with 332,585 more rows

fraction 열 추가

babynames %>%
  group_by(year) %>%
  mutate(year_total = sum(number)) %>%
  ungroup() %>%
  mutate(fraction = number / year_total)

# A tibble: 332,595 x 5
    year name    number year_total  fraction
   <dbl> <chr>    <int>      <int>     <dbl>
 1  1880 Aaron      102     201478 0.000506 
 2  1880 Ab           5     201478 0.0000248
 3  1880 Abbie       71     201478 0.000352 
 4  1880 Abbott       5     201478 0.0000248
 5  1880 Abby         6     201478 0.0000298
 6  1880 Abe         50     201478 0.000248 
 7  1880 Abel         9     201478 0.0000447
 8  1880 Abigail     12     201478 0.0000596
 9  1880 Abner       27     201478 0.000134 
10  1880 Abraham     81     201478 0.000402 
# … with 332,585 more rows

시각화 비교

선택한 이름 그래프

이름 그래프: 그룹화된 mutate

연습해 봅시다!

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