Import data

flights
## # A tibble: 336,776 × 19
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013     1     1      517            515         2      830            819
##  2  2013     1     1      533            529         4      850            830
##  3  2013     1     1      542            540         2      923            850
##  4  2013     1     1      544            545        -1     1004           1022
##  5  2013     1     1      554            600        -6      812            837
##  6  2013     1     1      554            558        -4      740            728
##  7  2013     1     1      555            600        -5      913            854
##  8  2013     1     1      557            600        -3      709            723
##  9  2013     1     1      557            600        -3      838            846
## 10  2013     1     1      558            600        -2      753            745
## # ℹ 336,766 more rows
## # ℹ 11 more variables: 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>

Filter rows

filter(flights, month ==1, day == 1)
## # A tibble: 842 × 19
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013     1     1      517            515         2      830            819
##  2  2013     1     1      533            529         4      850            830
##  3  2013     1     1      542            540         2      923            850
##  4  2013     1     1      544            545        -1     1004           1022
##  5  2013     1     1      554            600        -6      812            837
##  6  2013     1     1      554            558        -4      740            728
##  7  2013     1     1      555            600        -5      913            854
##  8  2013     1     1      557            600        -3      709            723
##  9  2013     1     1      557            600        -3      838            846
## 10  2013     1     1      558            600        -2      753            745
## # ℹ 832 more rows
## # ℹ 11 more variables: 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>

Arrange rows

arrange(flights, desc(month), desc(day))
## # A tibble: 336,776 × 19
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013    12    31       13           2359        14      439            437
##  2  2013    12    31       18           2359        19      449            444
##  3  2013    12    31       26           2245       101      129           2353
##  4  2013    12    31      459            500        -1      655            651
##  5  2013    12    31      514            515        -1      814            812
##  6  2013    12    31      549            551        -2      925            900
##  7  2013    12    31      550            600       -10      725            745
##  8  2013    12    31      552            600        -8      811            826
##  9  2013    12    31      553            600        -7      741            754
## 10  2013    12    31      554            550         4     1024           1027
## # ℹ 336,766 more rows
## # ℹ 11 more variables: 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>

Select columns

select(flights, year:dep_time)
## # A tibble: 336,776 × 4
##     year month   day dep_time
##    <int> <int> <int>    <int>
##  1  2013     1     1      517
##  2  2013     1     1      533
##  3  2013     1     1      542
##  4  2013     1     1      544
##  5  2013     1     1      554
##  6  2013     1     1      554
##  7  2013     1     1      555
##  8  2013     1     1      557
##  9  2013     1     1      557
## 10  2013     1     1      558
## # ℹ 336,766 more rows
select(flights, year, month, day, dep_time)
## # A tibble: 336,776 × 4
##     year month   day dep_time
##    <int> <int> <int>    <int>
##  1  2013     1     1      517
##  2  2013     1     1      533
##  3  2013     1     1      542
##  4  2013     1     1      544
##  5  2013     1     1      554
##  6  2013     1     1      554
##  7  2013     1     1      555
##  8  2013     1     1      557
##  9  2013     1     1      557
## 10  2013     1     1      558
## # ℹ 336,766 more rows

Add columns

Add columns

mutate(flights,
       gain = dep_delay - arr_delay)
## # A tibble: 336,776 × 20
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013     1     1      517            515         2      830            819
##  2  2013     1     1      533            529         4      850            830
##  3  2013     1     1      542            540         2      923            850
##  4  2013     1     1      544            545        -1     1004           1022
##  5  2013     1     1      554            600        -6      812            837
##  6  2013     1     1      554            558        -4      740            728
##  7  2013     1     1      555            600        -5      913            854
##  8  2013     1     1      557            600        -3      709            723
##  9  2013     1     1      557            600        -3      838            846
## 10  2013     1     1      558            600        -2      753            745
## # ℹ 336,766 more rows
## # ℹ 12 more variables: 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>, gain <dbl>

Summarize by groups

flights
## # A tibble: 336,776 × 19
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013     1     1      517            515         2      830            819
##  2  2013     1     1      533            529         4      850            830
##  3  2013     1     1      542            540         2      923            850
##  4  2013     1     1      544            545        -1     1004           1022
##  5  2013     1     1      554            600        -6      812            837
##  6  2013     1     1      554            558        -4      740            728
##  7  2013     1     1      555            600        -5      913            854
##  8  2013     1     1      557            600        -3      709            723
##  9  2013     1     1      557            600        -3      838            846
## 10  2013     1     1      558            600        -2      753            745
## # ℹ 336,766 more rows
## # ℹ 11 more variables: 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>
# average departure delay
summarise(flights, mean(dep_delay, na.rm = TRUE))
## # A tibble: 1 × 1
##   `mean(dep_delay, na.rm = TRUE)`
##                             <dbl>
## 1                            12.6
flights %>%
    
    #group by airlines
    group_by(carrier) %>%
    
    # calculate average departure delay
    summarise (delay = mean(dep_delay, na.rm = TRUE)) %>%
    
    #sort it 
    arrange(delay)
## # A tibble: 16 × 2
##    carrier delay
##    <chr>   <dbl>
##  1 US       3.78
##  2 HA       4.90
##  3 AS       5.80
##  4 AA       8.59
##  5 DL       9.26
##  6 MQ      10.6 
##  7 UA      12.1 
##  8 OO      12.6 
##  9 VX      12.9 
## 10 B6      13.0 
## 11 9E      16.7 
## 12 WN      17.7 
## 13 FL      18.7 
## 14 YV      19.0 
## 15 EV      20.0 
## 16 F9      20.2
flights %>%
    group_by(dest) %>%
    summarise(count = n(),
              dist = mean(distance, na.rm = TRUE),
              delay = mean(arr_delay, na.rm = TRUE)) %>%
    
    # plot
    ggplot(mapping = aes(x = dist, y = delay)) +
    geom_point(aes(size = count), alpha = 0.3) +
    geom_smooth(se = FALSE)
## `geom_smooth()` using method = 'loess' and formula = 'y ~ x'
## Warning: Removed 1 row containing non-finite outside the scale range
## (`stat_smooth()`).
## Warning: Removed 1 row containing missing values or values outside the scale range
## (`geom_point()`).

flights %>% 
    
    # remove missing values
    filter(is.na(dep_delay))
## # A tibble: 8,255 × 19
##     year month   day dep_time sched_dep_time dep_delay arr_time sched_arr_time
##    <int> <int> <int>    <int>          <int>     <dbl>    <int>          <int>
##  1  2013     1     1       NA           1630        NA       NA           1815
##  2  2013     1     1       NA           1935        NA       NA           2240
##  3  2013     1     1       NA           1500        NA       NA           1825
##  4  2013     1     1       NA            600        NA       NA            901
##  5  2013     1     2       NA           1540        NA       NA           1747
##  6  2013     1     2       NA           1620        NA       NA           1746
##  7  2013     1     2       NA           1355        NA       NA           1459
##  8  2013     1     2       NA           1420        NA       NA           1644
##  9  2013     1     2       NA           1321        NA       NA           1536
## 10  2013     1     2       NA           1545        NA       NA           1910
## # ℹ 8,245 more rows
## # ℹ 11 more variables: 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>
flights %>%
    group_by(year, month, day) %>%
    summarise(count = n())
## `summarise()` has grouped output by 'year', 'month'. You can override using the
## `.groups` argument.
## # A tibble: 365 × 4
## # Groups:   year, month [12]
##     year month   day count
##    <int> <int> <int> <int>
##  1  2013     1     1   842
##  2  2013     1     2   943
##  3  2013     1     3   914
##  4  2013     1     4   915
##  5  2013     1     5   720
##  6  2013     1     6   832
##  7  2013     1     7   933
##  8  2013     1     8   899
##  9  2013     1     9   902
## 10  2013     1    10   932
## # ℹ 355 more rows