pacman::p_load(nycflights13)
summary(flights)
##       year          month             day           dep_time    sched_dep_time
##  Min.   :2013   Min.   : 1.000   Min.   : 1.00   Min.   :   1   Min.   : 106  
##  1st Qu.:2013   1st Qu.: 4.000   1st Qu.: 8.00   1st Qu.: 907   1st Qu.: 906  
##  Median :2013   Median : 7.000   Median :16.00   Median :1401   Median :1359  
##  Mean   :2013   Mean   : 6.549   Mean   :15.71   Mean   :1349   Mean   :1344  
##  3rd Qu.:2013   3rd Qu.:10.000   3rd Qu.:23.00   3rd Qu.:1744   3rd Qu.:1729  
##  Max.   :2013   Max.   :12.000   Max.   :31.00   Max.   :2400   Max.   :2359  
##                                                  NA's   :8255                 
##    dep_delay          arr_time    sched_arr_time   arr_delay       
##  Min.   : -43.00   Min.   :   1   Min.   :   1   Min.   : -86.000  
##  1st Qu.:  -5.00   1st Qu.:1104   1st Qu.:1124   1st Qu.: -17.000  
##  Median :  -2.00   Median :1535   Median :1556   Median :  -5.000  
##  Mean   :  12.64   Mean   :1502   Mean   :1536   Mean   :   6.895  
##  3rd Qu.:  11.00   3rd Qu.:1940   3rd Qu.:1945   3rd Qu.:  14.000  
##  Max.   :1301.00   Max.   :2400   Max.   :2359   Max.   :1272.000  
##  NA's   :8255      NA's   :8713                  NA's   :9430      
##    carrier              flight       tailnum             origin         
##  Length:336776      Min.   :   1   Length:336776      Length:336776     
##  Class :character   1st Qu.: 553   Class :character   Class :character  
##  Mode  :character   Median :1496   Mode  :character   Mode  :character  
##                     Mean   :1972                                        
##                     3rd Qu.:3465                                        
##                     Max.   :8500                                        
##                                                                         
##      dest              air_time        distance         hour      
##  Length:336776      Min.   : 20.0   Min.   :  17   Min.   : 1.00  
##  Class :character   1st Qu.: 82.0   1st Qu.: 502   1st Qu.: 9.00  
##  Mode  :character   Median :129.0   Median : 872   Median :13.00  
##                     Mean   :150.7   Mean   :1040   Mean   :13.18  
##                     3rd Qu.:192.0   3rd Qu.:1389   3rd Qu.:17.00  
##                     Max.   :695.0   Max.   :4983   Max.   :23.00  
##                     NA's   :9430                                  
##      minute        time_hour                  
##  Min.   : 0.00   Min.   :2013-01-01 05:00:00  
##  1st Qu.: 8.00   1st Qu.:2013-04-04 13:00:00  
##  Median :29.00   Median :2013-07-03 10:00:00  
##  Mean   :26.23   Mean   :2013-07-03 05:22:54  
##  3rd Qu.:44.00   3rd Qu.:2013-10-01 07:00:00  
##  Max.   :59.00   Max.   :2013-12-31 23:00:00  
## 
maxdep <- max(flights$dep_delay, na.rm=TRUE)

maxdep_id <- which(flights$dep_delay==maxdep)

flights[maxdep_id, 10:12]
## # A tibble: 1 × 3
##   carrier flight tailnum
##   <chr>    <int> <chr>  
## 1 HA          51 N384HA
library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
not_cancelled <- flights %>%
  filter(!is.na(arr_delay)) 

lowest_tailnum <- not_cancelled %>%
  group_by(tailnum) %>%       
  summarise(avg_arr_delay = mean(arr_delay)) %>%  
  arrange(avg_arr_delay) %>%  
  slice(1)                   

lowest_tailnum
## # A tibble: 1 × 2
##   tailnum avg_arr_delay
##   <chr>           <dbl>
## 1 N560AS            -53
not_cancelled %>%
  group_by(year, month, day) %>%
  summarise(
    first = min(dep_time, na.rm = TRUE),
    last  = max(dep_time, na.rm = TRUE)
  ) %>%
  arrange(desc(last)) %>%
  head(10) 
## `summarise()` has grouped output by 'year', 'month'. You can override using the
## `.groups` argument.
## # A tibble: 10 × 5
## # Groups:   year, month [5]
##     year month   day first  last
##    <int> <int> <int> <int> <int>
##  1  2013     2     7    27  2400
##  2  2013     2    11     1  2400
##  3  2013     3    15    11  2400
##  4  2013     3    22    37  2400
##  5  2013     3    25    13  2400
##  6  2013     4     2     9  2400
##  7  2013     4     4    14  2400
##  8  2013     4    20     7  2400
##  9  2013     5    21   110  2400
## 10  2013     6    17     2  2400
library(dplyr)

not_cancelled %>%
  group_by(month) %>%
  summarise(
    proportion = mean(dep_delay > 60, na.rm = TRUE)
  ) %>%
  arrange(desc(proportion))
## # A tibble: 12 × 2
##    month proportion
##    <int>      <dbl>
##  1     7     0.133 
##  2     6     0.128 
##  3    12     0.0936
##  4     4     0.0909
##  5     3     0.0832
##  6     5     0.0812
##  7     8     0.0794
##  8     2     0.0694
##  9     1     0.0685
## 10     9     0.0486
## 11    10     0.0469
## 12    11     0.0401
flights %>%
  group_by(dest) %>%
  summarise(num_carriers = n_distinct(carrier)) %>%
  arrange(desc(num_carriers))
## # A tibble: 105 × 2
##    dest  num_carriers
##    <chr>        <int>
##  1 ATL              7
##  2 BOS              7
##  3 CLT              7
##  4 ORD              7
##  5 TPA              7
##  6 AUS              6
##  7 DCA              6
##  8 DTW              6
##  9 IAD              6
## 10 MSP              6
## # ℹ 95 more rows