dplyr

Disini saya akan mencoba belajar tentang “Data Wrangling”. “Data Wrangling” adalah suatu usaha agar data yang saya miliki menjadi bentuk yang dapat digunakan/berguna untuk melakukan “vizualitation” dan “modelling”. Pada bagian ini saya akan belajar tentang merapikan data menggunakan dplyr. Sebagain pernah dicoba-coba pada bagian dplyr.

library(tidyverse)
# agar dapat menggunakan dataset yang ada pada package ini
library(nycflights13)

Dataset yang digunakan adalah sebagai berikut:

airlines
## # A tibble: 16 x 2
##    carrier name                       
##    <chr>   <chr>                      
##  1 9E      Endeavor Air Inc.          
##  2 AA      American Airlines Inc.     
##  3 AS      Alaska Airlines Inc.       
##  4 B6      JetBlue Airways            
##  5 DL      Delta Air Lines Inc.       
##  6 EV      ExpressJet Airlines Inc.   
##  7 F9      Frontier Airlines Inc.     
##  8 FL      AirTran Airways Corporation
##  9 HA      Hawaiian Airlines Inc.     
## 10 MQ      Envoy Air                  
## 11 OO      SkyWest Airlines Inc.      
## 12 UA      United Air Lines Inc.      
## 13 US      US Airways Inc.            
## 14 VX      Virgin America             
## 15 WN      Southwest Airlines Co.     
## 16 YV      Mesa Airlines Inc.
airports
## # A tibble: 1,458 x 8
##    faa   name                       lat    lon   alt    tz dst   tzone          
##    <chr> <chr>                    <dbl>  <dbl> <dbl> <dbl> <chr> <chr>          
##  1 04G   Lansdowne Airport         41.1  -80.6  1044    -5 A     America/New_Yo~
##  2 06A   Moton Field Municipal A~  32.5  -85.7   264    -6 A     America/Chicago
##  3 06C   Schaumburg Regional       42.0  -88.1   801    -6 A     America/Chicago
##  4 06N   Randall Airport           41.4  -74.4   523    -5 A     America/New_Yo~
##  5 09J   Jekyll Island Airport     31.1  -81.4    11    -5 A     America/New_Yo~
##  6 0A9   Elizabethton Municipal ~  36.4  -82.2  1593    -5 A     America/New_Yo~
##  7 0G6   Williams County Airport   41.5  -84.5   730    -5 A     America/New_Yo~
##  8 0G7   Finger Lakes Regional A~  42.9  -76.8   492    -5 A     America/New_Yo~
##  9 0P2   Shoestring Aviation Air~  39.8  -76.6  1000    -5 U     America/New_Yo~
## 10 0S9   Jefferson County Intl     48.1 -123.    108    -8 A     America/Los_An~
## # ... with 1,448 more rows
planes
## # A tibble: 3,322 x 9
##    tailnum  year type          manufacturer   model  engines seats speed engine 
##    <chr>   <int> <chr>         <chr>          <chr>    <int> <int> <int> <chr>  
##  1 N10156   2004 Fixed wing m~ EMBRAER        EMB-1~       2    55    NA Turbo-~
##  2 N102UW   1998 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  3 N103US   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  4 N104UW   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  5 N10575   2002 Fixed wing m~ EMBRAER        EMB-1~       2    55    NA Turbo-~
##  6 N105UW   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  7 N107US   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  8 N108UW   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
##  9 N109UW   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
## 10 N110UW   1999 Fixed wing m~ AIRBUS INDUST~ A320-~       2   182    NA Turbo-~
## # ... with 3,312 more rows
weather
## # A tibble: 26,115 x 15
##    origin  year month   day  hour  temp  dewp humid wind_dir wind_speed
##    <chr>  <int> <int> <int> <int> <dbl> <dbl> <dbl>    <dbl>      <dbl>
##  1 EWR     2013     1     1     1  39.0  26.1  59.4      270      10.4 
##  2 EWR     2013     1     1     2  39.0  27.0  61.6      250       8.06
##  3 EWR     2013     1     1     3  39.0  28.0  64.4      240      11.5 
##  4 EWR     2013     1     1     4  39.9  28.0  62.2      250      12.7 
##  5 EWR     2013     1     1     5  39.0  28.0  64.4      260      12.7 
##  6 EWR     2013     1     1     6  37.9  28.0  67.2      240      11.5 
##  7 EWR     2013     1     1     7  39.0  28.0  64.4      240      15.0 
##  8 EWR     2013     1     1     8  39.9  28.0  62.2      250      10.4 
##  9 EWR     2013     1     1     9  39.9  28.0  62.2      260      15.0 
## 10 EWR     2013     1     1    10  41    28.0  59.6      260      13.8 
## # ... with 26,105 more rows, and 5 more variables: wind_gust <dbl>,
## #   precip <dbl>, pressure <dbl>, visib <dbl>, time_hour <dttm>
flights
## # A tibble: 336,776 x 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
## # ... with 336,766 more rows, and 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>

Key

Key adalah variabel atau set variabel yang secara unik mengidentifikasi pengamatan. Ada dua jenis “key”, yaitu “Primay Key” dan “Foreign Key”. Contoh “Primary Key”, setiap pesawat adalah teridentifikasi unik jika dilihat dari nomer ekor(nomer registrasi). Terlihat bahwa tidak ada pesawat yang memiliki nomor ekor (“tailnum”) lebih dari satu.Tailnum adalah “Primary Key”.

planes%>%
  count(tailnum)%>%
  filter(n>1)
## # A tibble: 0 x 2
## # ... with 2 variables: tailnum <chr>, n <int>

Primary Key juga bisa dalam kombinasi beberapa variabel.

weather%>%
  count(year,month,day,hour,origin,temp)%>%
  filter(n>1)
## # A tibble: 0 x 7
## # ... with 7 variables: year <int>, month <int>, day <int>, hour <int>,
## #   origin <chr>, temp <dbl>, n <int>

Namun terkadang juga “key” tidak mengidentifikasi secara unik pengamatan pada dataset tersebut, namun secara unik mengidentifikasikan secara unik pada dataset yang lain. Hal ini disebut “Foreign Key”. Contoh pada dataset flights, tailnum bukan unik pada dataset ini namun merupakan unik pada dataset plane.

flights%>%
  count(tailnum)%>%
  filter(n>1)
## # A tibble: 3,873 x 2
##    tailnum     n
##    <chr>   <int>
##  1 D942DN      4
##  2 N0EGMQ    371
##  3 N10156    153
##  4 N102UW     48
##  5 N103US     46
##  6 N104UW     47
##  7 N10575    289
##  8 N105UW     45
##  9 N107US     41
## 10 N108UW     60
## # ... with 3,863 more rows

Mutating Joins

Misal saya ingin menambahkan nama pesawat pada dataset flights. Dan disini saya hanya ingin melihat variabel (year, month, day, hour,tailnum,carrier)

flights%>%
  select(year:day, hour,tailnum,carrier)%>%
  left_join(airlines, by="carrier")
## # A tibble: 336,776 x 7
##     year month   day  hour tailnum carrier name                    
##    <int> <int> <int> <dbl> <chr>   <chr>   <chr>                   
##  1  2013     1     1     5 N14228  UA      United Air Lines Inc.   
##  2  2013     1     1     5 N24211  UA      United Air Lines Inc.   
##  3  2013     1     1     5 N619AA  AA      American Airlines Inc.  
##  4  2013     1     1     5 N804JB  B6      JetBlue Airways         
##  5  2013     1     1     6 N668DN  DL      Delta Air Lines Inc.    
##  6  2013     1     1     5 N39463  UA      United Air Lines Inc.   
##  7  2013     1     1     6 N516JB  B6      JetBlue Airways         
##  8  2013     1     1     6 N829AS  EV      ExpressJet Airlines Inc.
##  9  2013     1     1     6 N593JB  B6      JetBlue Airways         
## 10  2013     1     1     6 N3ALAA  AA      American Airlines Inc.  
## # ... with 336,766 more rows

Hasilnya samadengan yang diatas. Carrier adalah “Key”.

flights%>%
  select(year:day, hour,tailnum,carrier)%>%
  mutate(name = airlines$name[match(carrier, airlines$carrier)])
## # A tibble: 336,776 x 7
##     year month   day  hour tailnum carrier name                    
##    <int> <int> <int> <dbl> <chr>   <chr>   <chr>                   
##  1  2013     1     1     5 N14228  UA      United Air Lines Inc.   
##  2  2013     1     1     5 N24211  UA      United Air Lines Inc.   
##  3  2013     1     1     5 N619AA  AA      American Airlines Inc.  
##  4  2013     1     1     5 N804JB  B6      JetBlue Airways         
##  5  2013     1     1     6 N668DN  DL      Delta Air Lines Inc.    
##  6  2013     1     1     5 N39463  UA      United Air Lines Inc.   
##  7  2013     1     1     6 N516JB  B6      JetBlue Airways         
##  8  2013     1     1     6 N829AS  EV      ExpressJet Airlines Inc.
##  9  2013     1     1     6 N593JB  B6      JetBlue Airways         
## 10  2013     1     1     6 N3ALAA  AA      American Airlines Inc.  
## # ... with 336,766 more rows

Understanding Join

Contoh Join

x<-tribble(
  ~key, ~val_x,
  1,"x1",
  2,"x2",
  3,"x3"
)
x
## # A tibble: 3 x 2
##     key val_x
##   <dbl> <chr>
## 1     1 x1   
## 2     2 x2   
## 3     3 x3
y<-tribble(
  ~key, ~val_y,
  1,"y1",
  2,"y2",
  4,"y3"
)
y
## # A tibble: 3 x 2
##     key val_y
##   <dbl> <chr>
## 1     1 y1   
## 2     2 y2   
## 3     4 y3
x%>%inner_join(y, by="key")
## # A tibble: 2 x 3
##     key val_x val_y
##   <dbl> <chr> <chr>
## 1     1 x1    y1   
## 2     2 x2    y2
x%>%left_join(y, by='key')
## # A tibble: 3 x 3
##     key val_x val_y
##   <dbl> <chr> <chr>
## 1     1 x1    y1   
## 2     2 x2    y2   
## 3     3 x3    <NA>
x%>%right_join(y, by='key')
## # A tibble: 3 x 3
##     key val_x val_y
##   <dbl> <chr> <chr>
## 1     1 x1    y1   
## 2     2 x2    y2   
## 3     4 <NA>  y3
x%>%full_join(y, by='key')
## # A tibble: 4 x 3
##     key val_x val_y
##   <dbl> <chr> <chr>
## 1     1 x1    y1   
## 2     2 x2    y2   
## 3     3 x3    <NA> 
## 4     4 <NA>  y3

Contoh Join pada Dataset

flights%>%
  left_join(weather)
## Joining, by = c("year", "month", "day", "origin", "hour", "time_hour")
## # A tibble: 336,776 x 28
##     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
## # ... with 336,766 more rows, and 20 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>,
## #   temp <dbl>, dewp <dbl>, humid <dbl>, wind_dir <dbl>, wind_speed <dbl>,
## #   wind_gust <dbl>, precip <dbl>, pressure <dbl>, visib <dbl>

Dest adalah “Key Foreign” pada flights, karena tailnum adalah “Key” pada airports, namun namanya adalah faa.

flights%>%
  left_join(airports, c("dest"="faa"))
## # A tibble: 336,776 x 26
##     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
## # ... with 336,766 more rows, and 18 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>,
## #   name <chr>, lat <dbl>, lon <dbl>, alt <dbl>, tz <dbl>, dst <chr>,
## #   tzone <chr>

Filtering join

Top 10 Destination

top_dest<-flights%>%
  count(dest, sort = T)%>%
  head(10)
top_dest
## # A tibble: 10 x 2
##    dest      n
##    <chr> <int>
##  1 ORD   17283
##  2 ATL   17215
##  3 LAX   16174
##  4 BOS   15508
##  5 MCO   14082
##  6 CLT   14064
##  7 SFO   13331
##  8 FLL   12055
##  9 MIA   11728
## 10 DCA    9705

Penerbangan ke top 10 destination

flights%>%
  filter(dest%in%top_dest$dest)
## # A tibble: 141,145 x 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      542            540         2      923            850
##  2  2013     1     1      554            600        -6      812            837
##  3  2013     1     1      554            558        -4      740            728
##  4  2013     1     1      555            600        -5      913            854
##  5  2013     1     1      557            600        -3      838            846
##  6  2013     1     1      558            600        -2      753            745
##  7  2013     1     1      558            600        -2      924            917
##  8  2013     1     1      558            600        -2      923            937
##  9  2013     1     1      559            559         0      702            706
## 10  2013     1     1      600            600         0      851            858
## # ... with 141,135 more rows, and 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>

Semijoin hanya menghubungkan dua tebel yang baris table1nya cocok dengan table2 (sama seperti diatas)

flights%>%
  semi_join(top_dest)
## Joining, by = "dest"
## # A tibble: 141,145 x 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      542            540         2      923            850
##  2  2013     1     1      554            600        -6      812            837
##  3  2013     1     1      554            558        -4      740            728
##  4  2013     1     1      555            600        -5      913            854
##  5  2013     1     1      557            600        -3      838            846
##  6  2013     1     1      558            600        -2      753            745
##  7  2013     1     1      558            600        -2      924            917
##  8  2013     1     1      558            600        -2      923            937
##  9  2013     1     1      559            559         0      702            706
## 10  2013     1     1      600            600         0      851            858
## # ... with 141,135 more rows, and 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>

Tambahan

Set Operations

df1<-tribble(
  ~a,~b,
  1,1,
  2,1
)
df1
## # A tibble: 2 x 2
##       a     b
##   <dbl> <dbl>
## 1     1     1
## 2     2     1
df2<-tribble(
  ~a,~b,
  1,1,
  1,2
)
df2
## # A tibble: 2 x 2
##       a     b
##   <dbl> <dbl>
## 1     1     1
## 2     1     2
intersect(df1,df2)
## # A tibble: 1 x 2
##       a     b
##   <dbl> <dbl>
## 1     1     1
union(df1,df2)
## # A tibble: 3 x 2
##       a     b
##   <dbl> <dbl>
## 1     1     1
## 2     2     1
## 3     1     2
setdiff(df1,df2)
## # A tibble: 1 x 2
##       a     b
##   <dbl> <dbl>
## 1     2     1
setdiff(df2,df1)
## # A tibble: 1 x 2
##       a     b
##   <dbl> <dbl>
## 1     1     2