第 4 章 選擇變數欄位
- select
選擇year, month, day變數
flights %>% select(year, month, day) ## # A tibble: 336,776 x 3
## year month day
## <int> <int> <int>
## 1 2013 1 1
## 2 2013 1 1
## 3 2013 1 1
## 4 2013 1 1
## 5 2013 1 1
## 6 2013 1 1
## 7 2013 1 1
## 8 2013 1 1
## 9 2013 1 1
## 10 2013 1 1
## # ... with 336,766 more rows選擇year到day欄變數
flights %>% select(year:day) ## # A tibble: 336,776 x 3
## year month day
## <int> <int> <int>
## 1 2013 1 1
## 2 2013 1 1
## 3 2013 1 1
## 4 2013 1 1
## 5 2013 1 1
## 6 2013 1 1
## 7 2013 1 1
## 8 2013 1 1
## 9 2013 1 1
## 10 2013 1 1
## # ... with 336,766 more rows選擇year到day以外的欄位
flights %>% select(-(year:day)) ## # A tibble: 336,776 x 16
## dep_time sched_dep_time dep_delay arr_time
## <int> <int> <dbl> <int>
## 1 517 515 2 830
## 2 533 529 4 850
## 3 542 540 2 923
## 4 544 545 -1 1004
## 5 554 600 -6 812
## 6 554 558 -4 740
## 7 555 600 -5 913
## 8 557 600 -3 709
## 9 557 600 -3 838
## 10 558 600 -2 753
## # ... with 336,766 more rows, and 12 more variables:
## # sched_arr_time <int>, arr_delay <dbl>,
## # carrier <chr>, flight <int>, tailnum <chr>,
## # origin <chr>, dest <chr>, air_time <dbl>,
## # distance <dbl>, hour <dbl>, minute <dbl>,
## # time_hour <dttm>練習二：只留下 成績資料 科目名稱 及 授課老師 變數