U većini slučajeva, kada radite s odgovorom primljenim od API-ja ili s bilo kojim drugim podacima koji imaju složenu strukturu stabla, suočeni ste s JSON i XML formatima.
Ovi formati imaju mnoge prednosti: pohranjuju podatke prilično kompaktno i omogućuju vam da izbjegnete nepotrebno dupliciranje informacija.
Nedostatak ovih formata je složenost njihove obrade i analize. Nestrukturirani podaci ne mogu se koristiti u izračunima i na njima se ne može graditi vizualizacija.
Ovaj članak je logičan nastavak publikacije . Pomoću paketa pomoći će vam dovesti strukture nestrukturiranih podataka u poznati i prikladan za analizu tablični oblik tidyr, uvršten u jezgru knjižnice tidyverse, i njegovu obitelj funkcija unnest_*().
sadržaj
Ako vas zanima analiza podataka, možda će vas zanimati moja и kanala. Većina sadržaja posvećena je jeziku R.
Uvod
Pravokutnik (napomena prevoditelja, nisam našao odgovarajuće mogućnosti prijevoda za ovaj izraz, pa ćemo ostaviti kako jest.) je proces dovođenja nestrukturiranih podataka s ugniježđenim nizovima u dvodimenzionalnu tablicu koja se sastoji od poznatih redaka i stupaca. U tidyr Postoji nekoliko funkcija koje će vam pomoći da proširite stupce ugniježđenog popisa i smanjite podatke u pravokutni, tablični oblik:
unnest_longer()uzima svaki element popisa stupaca i stvara novi red.unnest_wider()uzima svaki element popisa stupaca i stvara novi stupac.unnest_auto()automatski određuje koju je funkciju najbolje koristiti
unnest_longer()iliunnest_wider().hoist()sličnounnest_wider()ali odabire samo navedene komponente i omogućuje vam rad s nekoliko razina gniježđenja.
Većina problema povezanih s dovođenjem nestrukturiranih podataka s nekoliko razina ugniježđenja u dvodimenzionalnu tablicu može se riješiti kombiniranjem navedenih funkcija s dplyr.
Kako bismo demonstrirali ove tehnike, koristit ćemo paket repurrrsive, koji pruža više složenih popisa na više razina izvedenih iz web API-ja.
library(tidyr)
library(dplyr)
library(repurrrsive)Korisnici GitHuba
Počnimo s tim gh_korisnici, popis koji sadrži informacije o šest GitHub korisnika. Prvo transformirajmo popis gh_korisnici в cvokotati okvir:
users <- tibble( user = gh_users ) Ovo se čini pomalo kontraintuitivnim: zašto dati popis gh_korisnici, do složenije strukture podataka? No podatkovni okvir ima veliku prednost: kombinira više vektora tako da se sve prati u jednom objektu.
Svaki element objekta users je imenovana lista u kojoj svaki element predstavlja stupac.
names(users$user[[1]])
#> [1] "login" "id" "avatar_url"
#> [4] "gravatar_id" "url" "html_url"
#> [7] "followers_url" "following_url" "gists_url"
#> [10] "starred_url" "subscriptions_url" "organizations_url"
#> [13] "repos_url" "events_url" "received_events_url"
#> [16] "type" "site_admin" "name"
#> [19] "company" "blog" "location"
#> [22] "email" "hireable" "bio"
#> [25] "public_repos" "public_gists" "followers"
#> [28] "following" "created_at" "updated_at"Postoje dva načina za pretvaranje komponenti popisa u stupce. unnest_wider() uzima svaku komponentu i stvara novi stupac:
users %>% unnest_wider(user)
#> # A tibble: 6 x 30
#> login id avatar_url gravatar_id url html_url followers_url
#> <chr> <int> <chr> <chr> <chr> <chr> <chr>
#> 1 gabo… 6.60e5 https://a… "" http… https:/… https://api.…
#> 2 jenn… 5.99e5 https://a… "" http… https:/… https://api.…
#> 3 jtle… 1.57e6 https://a… "" http… https:/… https://api.…
#> 4 juli… 1.25e7 https://a… "" http… https:/… https://api.…
#> 5 leep… 3.51e6 https://a… "" http… https:/… https://api.…
#> 6 masa… 8.36e6 https://a… "" http… https:/… https://api.…
#> # … with 23 more variables: following_url <chr>, gists_url <chr>,
#> # starred_url <chr>, subscriptions_url <chr>, organizations_url <chr>,
#> # repos_url <chr>, events_url <chr>, received_events_url <chr>,
#> # type <chr>, site_admin <lgl>, name <chr>, company <chr>, blog <chr>,
#> # location <chr>, email <chr>, public_repos <int>, public_gists <int>,
#> # followers <int>, following <int>, created_at <chr>, updated_at <chr>,
#> # bio <chr>, hireable <lgl>U ovom slučaju imamo tablicu koja se sastoji od 30 stupaca, a većina nam neće trebati, pa možemo umjesto unnest_wider() za korištenje hoist(). hoist() omogućuje nam izdvajanje odabranih komponenti koristeći istu sintaksu kao purrr::pluck():
users %>% hoist(user,
followers = "followers",
login = "login",
url = "html_url"
)
#> # A tibble: 6 x 4
#> followers login url user
#> <int> <chr> <chr> <list>
#> 1 303 gaborcsardi https://github.com/gaborcsardi <named list [27]>
#> 2 780 jennybc https://github.com/jennybc <named list [27]>
#> 3 3958 jtleek https://github.com/jtleek <named list [27]>
#> 4 115 juliasilge https://github.com/juliasilge <named list [27]>
#> 5 213 leeper https://github.com/leeper <named list [27]>
#> 6 34 masalmon https://github.com/masalmon <named list [27]>hoist() uklanja navedene imenovane komponente s popisa stupaca korisniktako da možete razmotriti hoist() poput premještanja komponenti s internog popisa okvira datuma na njegovu najvišu razinu.
Github repozitoriji
Usklađivanje popisa gh_repos počinjemo slično pretvarajući ga u tibble:
repos <- tibble(repo = gh_repos)
repos
#> # A tibble: 6 x 1
#> repo
#> <list>
#> 1 <list [30]>
#> 2 <list [30]>
#> 3 <list [30]>
#> 4 <list [26]>
#> 5 <list [30]>
#> 6 <list [30]>Ovaj put elementi korisnik predstavljaju popis repozitorija u vlasništvu ovog korisnika. Svaki repozitorij je zasebna opservacija, dakle prema konceptu urednih podataka (približno uredni podaci) trebali bi postati novi redovi, što je razlog zašto koristimo unnest_longer() ali ne unnest_wider():
repos <- repos %>% unnest_longer(repo)
repos
#> # A tibble: 176 x 1
#> repo
#> <list>
#> 1 <named list [68]>
#> 2 <named list [68]>
#> 3 <named list [68]>
#> 4 <named list [68]>
#> 5 <named list [68]>
#> 6 <named list [68]>
#> 7 <named list [68]>
#> 8 <named list [68]>
#> 9 <named list [68]>
#> 10 <named list [68]>
#> # … with 166 more rowsSada možemo koristiti unnest_wider() ili hoist() :
repos %>% hoist(repo,
login = c("owner", "login"),
name = "name",
homepage = "homepage",
watchers = "watchers_count"
)
#> # A tibble: 176 x 5
#> login name homepage watchers repo
#> <chr> <chr> <chr> <int> <list>
#> 1 gaborcsardi after <NA> 5 <named list [65]>
#> 2 gaborcsardi argufy <NA> 19 <named list [65]>
#> 3 gaborcsardi ask <NA> 5 <named list [65]>
#> 4 gaborcsardi baseimports <NA> 0 <named list [65]>
#> 5 gaborcsardi citest <NA> 0 <named list [65]>
#> 6 gaborcsardi clisymbols "" 18 <named list [65]>
#> 7 gaborcsardi cmaker <NA> 0 <named list [65]>
#> 8 gaborcsardi cmark <NA> 0 <named list [65]>
#> 9 gaborcsardi conditions <NA> 0 <named list [65]>
#> 10 gaborcsardi crayon <NA> 52 <named list [65]>
#> # … with 166 more rowsObratite pozornost na uporabu c("owner", "login"): Ovo nam omogućuje da dobijemo vrijednost druge razine iz ugniježđene liste owner. Alternativni pristup je dobiti cijeli popis owner a zatim pomoću funkcije unnest_wider() svaki njegov element staviti u stupac:
repos %>%
hoist(repo, owner = "owner") %>%
unnest_wider(owner)
#> # A tibble: 176 x 18
#> login id avatar_url gravatar_id url html_url followers_url
#> <chr> <int> <chr> <chr> <chr> <chr> <chr>
#> 1 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 2 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 3 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 4 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 5 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 6 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 7 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 8 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 9 gabo… 660288 https://a… "" http… https:/… https://api.…
#> 10 gabo… 660288 https://a… "" http… https:/… https://api.…
#> # … with 166 more rows, and 11 more variables: following_url <chr>,
#> # gists_url <chr>, starred_url <chr>, subscriptions_url <chr>,
#> # organizations_url <chr>, repos_url <chr>, events_url <chr>,
#> # received_events_url <chr>, type <chr>, site_admin <lgl>, repo <list>Umjesto razmišljanja o odabiru prave funkcije unnest_longer() ili unnest_wider() možeš koristiti unnest_auto(). Ova funkcija koristi nekoliko heurističkih metoda za odabir najprikladnije funkcije za transformaciju podataka i prikazuje poruku o odabranoj metodi.
tibble(repo = gh_repos) %>%
unnest_auto(repo) %>%
unnest_auto(repo)
#> Using `unnest_longer(repo)`; no element has names
#> Using `unnest_wider(repo)`; elements have 68 names in common
#> # A tibble: 176 x 67
#> id name full_name owner private html_url description fork url
#> <int> <chr> <chr> <lis> <lgl> <chr> <chr> <lgl> <chr>
#> 1 6.12e7 after gaborcsa… <nam… FALSE https:/… Run Code i… FALSE http…
#> 2 4.05e7 argu… gaborcsa… <nam… FALSE https:/… Declarativ… FALSE http…
#> 3 3.64e7 ask gaborcsa… <nam… FALSE https:/… Friendly C… FALSE http…
#> 4 3.49e7 base… gaborcsa… <nam… FALSE https:/… Do we get … FALSE http…
#> 5 6.16e7 cite… gaborcsa… <nam… FALSE https:/… Test R pac… TRUE http…
#> 6 3.39e7 clis… gaborcsa… <nam… FALSE https:/… Unicode sy… FALSE http…
#> 7 3.72e7 cmak… gaborcsa… <nam… FALSE https:/… port of cm… TRUE http…
#> 8 6.80e7 cmark gaborcsa… <nam… FALSE https:/… CommonMark… TRUE http…
#> 9 6.32e7 cond… gaborcsa… <nam… FALSE https:/… <NA> TRUE http…
#> 10 2.43e7 cray… gaborcsa… <nam… FALSE https:/… R package … FALSE http…
#> # … with 166 more rows, and 58 more variables: forks_url <chr>,
#> # keys_url <chr>, collaborators_url <chr>, teams_url <chr>,
#> # hooks_url <chr>, issue_events_url <chr>, events_url <chr>,
#> # assignees_url <chr>, branches_url <chr>, tags_url <chr>,
#> # blobs_url <chr>, git_tags_url <chr>, git_refs_url <chr>,
#> # trees_url <chr>, statuses_url <chr>, languages_url <chr>,
#> # stargazers_url <chr>, contributors_url <chr>, subscribers_url <chr>,
#> # subscription_url <chr>, commits_url <chr>, git_commits_url <chr>,
#> # comments_url <chr>, issue_comment_url <chr>, contents_url <chr>,
#> # compare_url <chr>, merges_url <chr>, archive_url <chr>,
#> # downloads_url <chr>, issues_url <chr>, pulls_url <chr>,
#> # milestones_url <chr>, notifications_url <chr>, labels_url <chr>,
#> # releases_url <chr>, deployments_url <chr>, created_at <chr>,
#> # updated_at <chr>, pushed_at <chr>, git_url <chr>, ssh_url <chr>,
#> # clone_url <chr>, svn_url <chr>, size <int>, stargazers_count <int>,
#> # watchers_count <int>, language <chr>, has_issues <lgl>,
#> # has_downloads <lgl>, has_wiki <lgl>, has_pages <lgl>,
#> # forks_count <int>, open_issues_count <int>, forks <int>,
#> # open_issues <int>, watchers <int>, default_branch <chr>,
#> # homepage <chr>Likovi iz Igre prijestolja
got_chars ima identičnu strukturu gh_users: Ovo je skup imenovanih popisa, gdje svaki element unutarnjeg popisa opisuje neki atribut lika iz Igre prijestolja. Dovođenje got_chars Za prikaz tablice započinjemo stvaranjem okvira datuma, baš kao u prethodnim primjerima, a zatim pretvaramo svaki element u zaseban stupac:
chars <- tibble(char = got_chars)
chars
#> # A tibble: 30 x 1
#> char
#> <list>
#> 1 <named list [18]>
#> 2 <named list [18]>
#> 3 <named list [18]>
#> 4 <named list [18]>
#> 5 <named list [18]>
#> 6 <named list [18]>
#> 7 <named list [18]>
#> 8 <named list [18]>
#> 9 <named list [18]>
#> 10 <named list [18]>
#> # … with 20 more rows
chars2 <- chars %>% unnest_wider(char)
chars2
#> # A tibble: 30 x 18
#> url id name gender culture born died alive titles aliases father
#> <chr> <int> <chr> <chr> <chr> <chr> <chr> <lgl> <list> <list> <chr>
#> 1 http… 1022 Theo… Male Ironbo… In 2… "" TRUE <chr … <chr [… ""
#> 2 http… 1052 Tyri… Male "" In 2… "" TRUE <chr … <chr [… ""
#> 3 http… 1074 Vict… Male Ironbo… In 2… "" TRUE <chr … <chr [… ""
#> 4 http… 1109 Will Male "" "" In 2… FALSE <chr … <chr [… ""
#> 5 http… 1166 Areo… Male Norvos… In 2… "" TRUE <chr … <chr [… ""
#> 6 http… 1267 Chett Male "" At H… In 2… FALSE <chr … <chr [… ""
#> 7 http… 1295 Cres… Male "" In 2… In 2… FALSE <chr … <chr [… ""
#> 8 http… 130 Aria… Female Dornish In 2… "" TRUE <chr … <chr [… ""
#> 9 http… 1303 Daen… Female Valyri… In 2… "" TRUE <chr … <chr [… ""
#> 10 http… 1319 Davo… Male Wester… In 2… "" TRUE <chr … <chr [… ""
#> # … with 20 more rows, and 7 more variables: mother <chr>, spouse <chr>,
#> # allegiances <list>, books <list>, povBooks <list>, tvSeries <list>,
#> # playedBy <list>Struktura got_chars nešto teže od gh_users, jer neke komponente popisa char sami su lista, kao rezultat dobivamo stupove - liste:
chars2 %>% select_if(is.list)
#> # A tibble: 30 x 7
#> titles aliases allegiances books povBooks tvSeries playedBy
#> <list> <list> <list> <list> <list> <list> <list>
#> 1 <chr [3]> <chr [4]> <chr [1]> <chr [3]> <chr [2]> <chr [6]> <chr [1]>
#> 2 <chr [2]> <chr [11]> <chr [1]> <chr [2]> <chr [4]> <chr [6]> <chr [1]>
#> 3 <chr [2]> <chr [1]> <chr [1]> <chr [3]> <chr [2]> <chr [1]> <chr [1]>
#> 4 <chr [1]> <chr [1]> <???> <chr [1]> <chr [1]> <chr [1]> <chr [1]>
#> 5 <chr [1]> <chr [1]> <chr [1]> <chr [3]> <chr [2]> <chr [2]> <chr [1]>
#> 6 <chr [1]> <chr [1]> <???> <chr [2]> <chr [1]> <chr [1]> <chr [1]>
#> 7 <chr [1]> <chr [1]> <???> <chr [2]> <chr [1]> <chr [1]> <chr [1]>
#> 8 <chr [1]> <chr [1]> <chr [1]> <chr [4]> <chr [1]> <chr [1]> <chr [1]>
#> 9 <chr [5]> <chr [11]> <chr [1]> <chr [1]> <chr [4]> <chr [6]> <chr [1]>
#> 10 <chr [4]> <chr [5]> <chr [2]> <chr [1]> <chr [3]> <chr [5]> <chr [1]>
#> # … with 20 more rowsVaši daljnji postupci ovise o ciljevima analize. Možda trebate staviti informacije u retke za svaku knjigu i seriju u kojoj se lik pojavljuje:
chars2 %>%
select(name, books, tvSeries) %>%
pivot_longer(c(books, tvSeries), names_to = "media", values_to = "value") %>%
unnest_longer(value)
#> # A tibble: 180 x 3
#> name media value
#> <chr> <chr> <chr>
#> 1 Theon Greyjoy books A Game of Thrones
#> 2 Theon Greyjoy books A Storm of Swords
#> 3 Theon Greyjoy books A Feast for Crows
#> 4 Theon Greyjoy tvSeries Season 1
#> 5 Theon Greyjoy tvSeries Season 2
#> 6 Theon Greyjoy tvSeries Season 3
#> 7 Theon Greyjoy tvSeries Season 4
#> 8 Theon Greyjoy tvSeries Season 5
#> 9 Theon Greyjoy tvSeries Season 6
#> 10 Tyrion Lannister books A Feast for Crows
#> # … with 170 more rowsIli možda želite izraditi tablicu koja vam omogućuje usklađivanje lika i djela:
chars2 %>%
select(name, title = titles) %>%
unnest_longer(title)
#> # A tibble: 60 x 2
#> name title
#> <chr> <chr>
#> 1 Theon Greyjoy Prince of Winterfell
#> 2 Theon Greyjoy Captain of Sea Bitch
#> 3 Theon Greyjoy Lord of the Iron Islands (by law of the green lands)
#> 4 Tyrion Lannister Acting Hand of the King (former)
#> 5 Tyrion Lannister Master of Coin (former)
#> 6 Victarion Greyjoy Lord Captain of the Iron Fleet
#> 7 Victarion Greyjoy Master of the Iron Victory
#> 8 Will ""
#> 9 Areo Hotah Captain of the Guard at Sunspear
#> 10 Chett ""
#> # … with 50 more rows(Obratite pažnju na prazne vrijednosti "" na terenu title, to je zbog pogrešaka prilikom unosa podataka u got_chars: zapravo, likovi za koje ne postoje odgovarajući naslovi knjiga i TV serija na terenu title mora imati vektor duljine 0, a ne vektor duljine 1 koji sadrži prazan niz.)
Gornji primjer možemo prepisati pomoću funkcije unnest_auto(). Ovaj pristup je prikladan za jednokratnu analizu, ali ne biste se trebali oslanjati na njega unnest_auto() za redovitu upotrebu. Poanta je da ako se vaša struktura podataka promijeni unnest_auto() može promijeniti odabrani mehanizam transformacije podataka ako je prvotno proširio stupce popisa u retke pomoću unnest_longer(), onda kada se struktura ulaznih podataka promijeni, logika se može promijeniti u korist unnest_wider(), a korištenje ovog pristupa na trajnoj osnovi može dovesti do neočekivanih pogrešaka.
tibble(char = got_chars) %>%
unnest_auto(char) %>%
select(name, title = titles) %>%
unnest_auto(title)
#> Using `unnest_wider(char)`; elements have 18 names in common
#> Using `unnest_longer(title)`; no element has names
#> # A tibble: 60 x 2
#> name title
#> <chr> <chr>
#> 1 Theon Greyjoy Prince of Winterfell
#> 2 Theon Greyjoy Captain of Sea Bitch
#> 3 Theon Greyjoy Lord of the Iron Islands (by law of the green lands)
#> 4 Tyrion Lannister Acting Hand of the King (former)
#> 5 Tyrion Lannister Master of Coin (former)
#> 6 Victarion Greyjoy Lord Captain of the Iron Fleet
#> 7 Victarion Greyjoy Master of the Iron Victory
#> 8 Will ""
#> 9 Areo Hotah Captain of the Guard at Sunspear
#> 10 Chett ""
#> # … with 50 more rowsGeokodiranje s Googleom
Zatim ćemo pogledati složeniju strukturu podataka dobivenih od Googleove usluge geokodiranja. Spremanje vjerodajnica u predmemoriju protivno je pravilima rada s API-jem za Google karte, pa ću prvo napisati jednostavan omotač oko API-ja. Koji se temelji na pohranjivanju API ključa Google Maps u varijablu okruženja; Ako nemate ključ za rad s API-jem za Google karte pohranjen u varijablama okruženja, fragmenti koda predstavljeni u ovom odjeljku neće se izvršiti.
has_key <- !identical(Sys.getenv("GOOGLE_MAPS_API_KEY"), "")
if (!has_key) {
message("No Google Maps API key found; code chunks will not be run")
}
# https://developers.google.com/maps/documentation/geocoding
geocode <- function(address, api_key = Sys.getenv("GOOGLE_MAPS_API_KEY")) {
url <- "https://maps.googleapis.com/maps/api/geocode/json"
url <- paste0(url, "?address=", URLencode(address), "&key=", api_key)
jsonlite::read_json(url)
}Popis koji ova funkcija vraća prilično je složen:
houston <- geocode("Houston TX")
str(houston)
#> List of 2
#> $ results:List of 1
#> ..$ :List of 5
#> .. ..$ address_components:List of 4
#> .. .. ..$ :List of 3
#> .. .. .. ..$ long_name : chr "Houston"
#> .. .. .. ..$ short_name: chr "Houston"
#> .. .. .. ..$ types :List of 2
#> .. .. .. .. ..$ : chr "locality"
#> .. .. .. .. ..$ : chr "political"
#> .. .. ..$ :List of 3
#> .. .. .. ..$ long_name : chr "Harris County"
#> .. .. .. ..$ short_name: chr "Harris County"
#> .. .. .. ..$ types :List of 2
#> .. .. .. .. ..$ : chr "administrative_area_level_2"
#> .. .. .. .. ..$ : chr "political"
#> .. .. ..$ :List of 3
#> .. .. .. ..$ long_name : chr "Texas"
#> .. .. .. ..$ short_name: chr "TX"
#> .. .. .. ..$ types :List of 2
#> .. .. .. .. ..$ : chr "administrative_area_level_1"
#> .. .. .. .. ..$ : chr "political"
#> .. .. ..$ :List of 3
#> .. .. .. ..$ long_name : chr "United States"
#> .. .. .. ..$ short_name: chr "US"
#> .. .. .. ..$ types :List of 2
#> .. .. .. .. ..$ : chr "country"
#> .. .. .. .. ..$ : chr "political"
#> .. ..$ formatted_address : chr "Houston, TX, USA"
#> .. ..$ geometry :List of 4
#> .. .. ..$ bounds :List of 2
#> .. .. .. ..$ northeast:List of 2
#> .. .. .. .. ..$ lat: num 30.1
#> .. .. .. .. ..$ lng: num -95
#> .. .. .. ..$ southwest:List of 2
#> .. .. .. .. ..$ lat: num 29.5
#> .. .. .. .. ..$ lng: num -95.8
#> .. .. ..$ location :List of 2
#> .. .. .. ..$ lat: num 29.8
#> .. .. .. ..$ lng: num -95.4
#> .. .. ..$ location_type: chr "APPROXIMATE"
#> .. .. ..$ viewport :List of 2
#> .. .. .. ..$ northeast:List of 2
#> .. .. .. .. ..$ lat: num 30.1
#> .. .. .. .. ..$ lng: num -95
#> .. .. .. ..$ southwest:List of 2
#> .. .. .. .. ..$ lat: num 29.5
#> .. .. .. .. ..$ lng: num -95.8
#> .. ..$ place_id : chr "ChIJAYWNSLS4QIYROwVl894CDco"
#> .. ..$ types :List of 2
#> .. .. ..$ : chr "locality"
#> .. .. ..$ : chr "political"
#> $ status : chr "OK"Srećom, problem pretvaranja ovih podataka u tablični oblik možemo riješiti korak po korak pomoću funkcija tidyr. Kako bih zadatak učinio malo izazovnijim i realističnijim, počet ću geokodiranjem nekoliko gradova:
city <- c ( "Houston" , "LA" , "New York" , "Chicago" , "Springfield" ) city_geo <- purrr::map (city, geocode) Dobiveni rezultat ću pretvoriti u tibble, zbog praktičnosti, dodat ću stupac s odgovarajućim nazivom grada.
loc <- tibble(city = city, json = city_geo)
loc
#> # A tibble: 5 x 2
#> city json
#> <chr> <list>
#> 1 Houston <named list [2]>
#> 2 LA <named list [2]>
#> 3 New York <named list [2]>
#> 4 Chicago <named list [2]>
#> 5 Springfield <named list [2]>Prva razina sadrži komponente status и result, kojim se možemo proširiti unnest_wider() :
loc %>%
unnest_wider(json)
#> # A tibble: 5 x 3
#> city results status
#> <chr> <list> <chr>
#> 1 Houston <list [1]> OK
#> 2 LA <list [1]> OK
#> 3 New York <list [1]> OK
#> 4 Chicago <list [1]> OK
#> 5 Springfield <list [1]> OKImajte na umu da results je popis na više razina. Većina gradova ima 1 element (koji predstavlja jedinstvenu vrijednost koja odgovara API-ju za geokodiranje), ali Springfield ima dva. Možemo ih izdvojiti u zasebne redove s unnest_longer() :
loc %>%
unnest_wider(json) %>%
unnest_longer(results)
#> # A tibble: 5 x 3
#> city results status
#> <chr> <list> <chr>
#> 1 Houston <named list [5]> OK
#> 2 LA <named list [5]> OK
#> 3 New York <named list [5]> OK
#> 4 Chicago <named list [5]> OK
#> 5 Springfield <named list [5]> OKSada svi imaju iste komponente, što se može provjeriti pomoću unnest_wider():
loc %>%
unnest_wider(json) %>%
unnest_longer(results) %>%
unnest_wider(results)
#> # A tibble: 5 x 7
#> city address_componen… formatted_addre… geometry place_id types status
#> <chr> <list> <chr> <list> <chr> <lis> <chr>
#> 1 Houst… <list [4]> Houston, TX, USA <named … ChIJAYWN… <lis… OK
#> 2 LA <list [4]> Los Angeles, CA… <named … ChIJE9on… <lis… OK
#> 3 New Y… <list [3]> New York, NY, U… <named … ChIJOwg_… <lis… OK
#> 4 Chica… <list [4]> Chicago, IL, USA <named … ChIJ7cv0… <lis… OK
#> 5 Sprin… <list [5]> Springfield, MO… <named … ChIJP5jI… <lis… OKProširivanjem popisa možemo pronaći koordinate zemljopisne širine i dužine svakog grada geometry:
loc %>%
unnest_wider(json) %>%
unnest_longer(results) %>%
unnest_wider(results) %>%
unnest_wider(geometry)
#> # A tibble: 5 x 10
#> city address_compone… formatted_addre… bounds location location_type
#> <chr> <list> <chr> <list> <list> <chr>
#> 1 Hous… <list [4]> Houston, TX, USA <name… <named … APPROXIMATE
#> 2 LA <list [4]> Los Angeles, CA… <name… <named … APPROXIMATE
#> 3 New … <list [3]> New York, NY, U… <name… <named … APPROXIMATE
#> 4 Chic… <list [4]> Chicago, IL, USA <name… <named … APPROXIMATE
#> 5 Spri… <list [5]> Springfield, MO… <name… <named … APPROXIMATE
#> # … with 4 more variables: viewport <list>, place_id <chr>, types <list>,
#> # status <chr>A zatim mjesto za koje se trebate proširiti location:
loc %>%
unnest_wider(json) %>%
unnest_longer(results) %>%
unnest_wider(results) %>%
unnest_wider(geometry) %>%
unnest_wider(location)
#> # A tibble: 5 x 11
#> city address_compone… formatted_addre… bounds lat lng location_type
#> <chr> <list> <chr> <list> <dbl> <dbl> <chr>
#> 1 Hous… <list [4]> Houston, TX, USA <name… 29.8 -95.4 APPROXIMATE
#> 2 LA <list [4]> Los Angeles, CA… <name… 34.1 -118. APPROXIMATE
#> 3 New … <list [3]> New York, NY, U… <name… 40.7 -74.0 APPROXIMATE
#> 4 Chic… <list [4]> Chicago, IL, USA <name… 41.9 -87.6 APPROXIMATE
#> 5 Spri… <list [5]> Springfield, MO… <name… 37.2 -93.3 APPROXIMATE
#> # … with 4 more variables: viewport <list>, place_id <chr>, types <list>,
#> # status <chr>Ipak opet, unnest_auto() pojednostavljuje opisanu operaciju uz neke rizike koji mogu biti uzrokovani promjenom strukture ulaznih podataka:
loc %>%
unnest_auto(json) %>%
unnest_auto(results) %>%
unnest_auto(results) %>%
unnest_auto(geometry) %>%
unnest_auto(location)
#> Using `unnest_wider(json)`; elements have 2 names in common
#> Using `unnest_longer(results)`; no element has names
#> Using `unnest_wider(results)`; elements have 5 names in common
#> Using `unnest_wider(geometry)`; elements have 4 names in common
#> Using `unnest_wider(location)`; elements have 2 names in common
#> # A tibble: 5 x 11
#> city address_compone… formatted_addre… bounds lat lng location_type
#> <chr> <list> <chr> <list> <dbl> <dbl> <chr>
#> 1 Hous… <list [4]> Houston, TX, USA <name… 29.8 -95.4 APPROXIMATE
#> 2 LA <list [4]> Los Angeles, CA… <name… 34.1 -118. APPROXIMATE
#> 3 New … <list [3]> New York, NY, U… <name… 40.7 -74.0 APPROXIMATE
#> 4 Chic… <list [4]> Chicago, IL, USA <name… 41.9 -87.6 APPROXIMATE
#> 5 Spri… <list [5]> Springfield, MO… <name… 37.2 -93.3 APPROXIMATE
#> # … with 4 more variables: viewport <list>, place_id <chr>, types <list>,
#> # status <chr>Također možemo samo pogledati prvu adresu za svaki grad:
loc %>%
unnest_wider(json) %>%
hoist(results, first_result = 1) %>%
unnest_wider(first_result) %>%
unnest_wider(geometry) %>%
unnest_wider(location)
#> # A tibble: 5 x 11
#> city address_compone… formatted_addre… bounds lat lng location_type
#> <chr> <list> <chr> <list> <dbl> <dbl> <chr>
#> 1 Hous… <list [4]> Houston, TX, USA <name… 29.8 -95.4 APPROXIMATE
#> 2 LA <list [4]> Los Angeles, CA… <name… 34.1 -118. APPROXIMATE
#> 3 New … <list [3]> New York, NY, U… <name… 40.7 -74.0 APPROXIMATE
#> 4 Chic… <list [4]> Chicago, IL, USA <name… 41.9 -87.6 APPROXIMATE
#> 5 Spri… <list [5]> Springfield, MO… <name… 37.2 -93.3 APPROXIMATE
#> # … with 4 more variables: viewport <list>, place_id <chr>, types <list>,
#> # status <chr>Ili koristiti hoist() za ronjenje na više razina na koje možete ići izravno lat и lng.
loc %>%
hoist(json,
lat = list("results", 1, "geometry", "location", "lat"),
lng = list("results", 1, "geometry", "location", "lng")
)
#> # A tibble: 5 x 4
#> city lat lng json
#> <chr> <dbl> <dbl> <list>
#> 1 Houston 29.8 -95.4 <named list [2]>
#> 2 LA 34.1 -118. <named list [2]>
#> 3 New York 40.7 -74.0 <named list [2]>
#> 4 Chicago 41.9 -87.6 <named list [2]>
#> 5 Springfield 37.2 -93.3 <named list [2]>Diskografija Sharle Gelfand
Na kraju ćemo se osvrnuti na najsloženiju strukturu - diskografiju Sharle Gelfand. Kao u gornjim primjerima, započinjemo pretvaranjem popisa u podatkovni okvir s jednim stupcem, a zatim ga proširujemo tako da je svaka komponenta zaseban stupac. Također pretvaram stupac date_added u odgovarajući format datuma i vremena u R.
discs <- tibble(disc = discog) %>%
unnest_wider(disc) %>%
mutate(date_added = as.POSIXct(strptime(date_added, "%Y-%m-%dT%H:%M:%S")))
discs
#> # A tibble: 155 x 5
#> instance_id date_added basic_information id rating
#> <int> <dttm> <list> <int> <int>
#> 1 354823933 2019-02-16 17:48:59 <named list [11]> 7496378 0
#> 2 354092601 2019-02-13 14:13:11 <named list [11]> 4490852 0
#> 3 354091476 2019-02-13 14:07:23 <named list [11]> 9827276 0
#> 4 351244906 2019-02-02 11:39:58 <named list [11]> 9769203 0
#> 5 351244801 2019-02-02 11:39:37 <named list [11]> 7237138 0
#> 6 351052065 2019-02-01 20:40:53 <named list [11]> 13117042 0
#> 7 350315345 2019-01-29 15:48:37 <named list [11]> 7113575 0
#> 8 350315103 2019-01-29 15:47:22 <named list [11]> 10540713 0
#> 9 350314507 2019-01-29 15:44:08 <named list [11]> 11260950 0
#> 10 350314047 2019-01-29 15:41:35 <named list [11]> 11726853 0
#> # … with 145 more rowsNa ovoj razini dobivamo informacije o tome kada je koji disk dodan u Sharlinu diskografiju, ali ne vidimo nikakve podatke o tim diskovima. Da bismo to učinili, moramo proširiti stupac basic_information:
discs %>% unnest_wider(basic_information)
#> Column name `id` must not be duplicated.
#> Use .name_repair to specify repair.Nažalost, dobit ćemo pogrešku jer... unutar popisa basic_information postoji istoimeni stupac basic_information. Ako se dogodi takva pogreška, možete upotrijebiti kako biste brzo utvrdili njezin uzrok names_repair = "unique":
discs %>% unnest_wider(basic_information, names_repair = "unique")
#> New names:
#> * id -> id...6
#> * id -> id...14
#> # A tibble: 155 x 15
#> instance_id date_added labels year artists id...6 thumb title
#> <int> <dttm> <list> <int> <list> <int> <chr> <chr>
#> 1 354823933 2019-02-16 17:48:59 <list… 2015 <list … 7.50e6 http… Demo
#> 2 354092601 2019-02-13 14:13:11 <list… 2013 <list … 4.49e6 http… Obse…
#> 3 354091476 2019-02-13 14:07:23 <list… 2017 <list … 9.83e6 http… I
#> 4 351244906 2019-02-02 11:39:58 <list… 2017 <list … 9.77e6 http… Oído…
#> 5 351244801 2019-02-02 11:39:37 <list… 2015 <list … 7.24e6 http… A Ca…
#> 6 351052065 2019-02-01 20:40:53 <list… 2019 <list … 1.31e7 http… Tash…
#> 7 350315345 2019-01-29 15:48:37 <list… 2014 <list … 7.11e6 http… Demo
#> 8 350315103 2019-01-29 15:47:22 <list… 2015 <list … 1.05e7 http… Let …
#> 9 350314507 2019-01-29 15:44:08 <list… 2017 <list … 1.13e7 "" Sub …
#> 10 350314047 2019-01-29 15:41:35 <list… 2017 <list … 1.17e7 http… Demo
#> # … with 145 more rows, and 7 more variables: formats <list>,
#> # cover_image <chr>, resource_url <chr>, master_id <int>,
#> # master_url <chr>, id...14 <int>, rating <int>Problem je u tome basic_information ponavlja ID stupac koji je također pohranjen na najvišoj razini, tako da ga možemo jednostavno ukloniti:
discs %>%
select(-id) %>%
unnest_wider(basic_information)
#> # A tibble: 155 x 14
#> instance_id date_added labels year artists id thumb title
#> <int> <dttm> <list> <int> <list> <int> <chr> <chr>
#> 1 354823933 2019-02-16 17:48:59 <list… 2015 <list … 7.50e6 http… Demo
#> 2 354092601 2019-02-13 14:13:11 <list… 2013 <list … 4.49e6 http… Obse…
#> 3 354091476 2019-02-13 14:07:23 <list… 2017 <list … 9.83e6 http… I
#> 4 351244906 2019-02-02 11:39:58 <list… 2017 <list … 9.77e6 http… Oído…
#> 5 351244801 2019-02-02 11:39:37 <list… 2015 <list … 7.24e6 http… A Ca…
#> 6 351052065 2019-02-01 20:40:53 <list… 2019 <list … 1.31e7 http… Tash…
#> 7 350315345 2019-01-29 15:48:37 <list… 2014 <list … 7.11e6 http… Demo
#> 8 350315103 2019-01-29 15:47:22 <list… 2015 <list … 1.05e7 http… Let …
#> 9 350314507 2019-01-29 15:44:08 <list… 2017 <list … 1.13e7 "" Sub …
#> 10 350314047 2019-01-29 15:41:35 <list… 2017 <list … 1.17e7 http… Demo
#> # … with 145 more rows, and 6 more variables: formats <list>,
#> # cover_image <chr>, resource_url <chr>, master_id <int>,
#> # master_url <chr>, rating <int>Alternativno, mogli bismo koristiti hoist():
discs %>%
hoist(basic_information,
title = "title",
year = "year",
label = list("labels", 1, "name"),
artist = list("artists", 1, "name")
)
#> # A tibble: 155 x 9
#> instance_id date_added title year label artist
#> <int> <dttm> <chr> <int> <chr> <chr>
#> 1 354823933 2019-02-16 17:48:59 Demo 2015 Tobi… Mollot
#> 2 354092601 2019-02-13 14:13:11 Obse… 2013 La V… Una B…
#> 3 354091476 2019-02-13 14:07:23 I 2017 La V… S.H.I…
#> 4 351244906 2019-02-02 11:39:58 Oído… 2017 La V… Rata …
#> 5 351244801 2019-02-02 11:39:37 A Ca… 2015 Kato… Ivy (…
#> 6 351052065 2019-02-01 20:40:53 Tash… 2019 High… Tashme
#> 7 350315345 2019-01-29 15:48:37 Demo 2014 Mind… Desgr…
#> 8 350315103 2019-01-29 15:47:22 Let … 2015 Not … Phant…
#> 9 350314507 2019-01-29 15:44:08 Sub … 2017 Not … Sub S…
#> 10 350314047 2019-01-29 15:41:35 Demo 2017 Pres… Small…
#> # … with 145 more rows, and 3 more variables: basic_information <list>,
#> # id <int>, rating <int>Ovdje brzo dohvaćam prvu etiketu i ime izvođača prema indeksu zaranjanjem u ugniježđeni popis.
Sustavniji pristup je stvaranje zasebnih tablica za izvođača i etiketu:
discs %>%
hoist(basic_information, artist = "artists") %>%
select(disc_id = id, artist) %>%
unnest_longer(artist) %>%
unnest_wider(artist)
#> # A tibble: 167 x 8
#> disc_id join name anv tracks role resource_url id
#> <int> <chr> <chr> <chr> <chr> <chr> <chr> <int>
#> 1 7496378 "" Mollot "" "" "" https://api.discog… 4.62e6
#> 2 4490852 "" Una Bèstia… "" "" "" https://api.discog… 3.19e6
#> 3 9827276 "" S.H.I.T. (… "" "" "" https://api.discog… 2.77e6
#> 4 9769203 "" Rata Negra "" "" "" https://api.discog… 4.28e6
#> 5 7237138 "" Ivy (18) "" "" "" https://api.discog… 3.60e6
#> 6 13117042 "" Tashme "" "" "" https://api.discog… 5.21e6
#> 7 7113575 "" Desgraciad… "" "" "" https://api.discog… 4.45e6
#> 8 10540713 "" Phantom He… "" "" "" https://api.discog… 4.27e6
#> 9 11260950 "" Sub Space … "" "" "" https://api.discog… 5.69e6
#> 10 11726853 "" Small Man … "" "" "" https://api.discog… 6.37e6
#> # … with 157 more rows
discs %>%
hoist(basic_information, format = "formats") %>%
select(disc_id = id, format) %>%
unnest_longer(format) %>%
unnest_wider(format) %>%
unnest_longer(descriptions)
#> # A tibble: 280 x 5
#> disc_id descriptions text name qty
#> <int> <chr> <chr> <chr> <chr>
#> 1 7496378 Numbered Black Cassette 1
#> 2 4490852 LP <NA> Vinyl 1
#> 3 9827276 "7"" <NA> Vinyl 1
#> 4 9827276 45 RPM <NA> Vinyl 1
#> 5 9827276 EP <NA> Vinyl 1
#> 6 9769203 LP <NA> Vinyl 1
#> 7 9769203 Album <NA> Vinyl 1
#> 8 7237138 "7"" <NA> Vinyl 1
#> 9 7237138 45 RPM <NA> Vinyl 1
#> 10 13117042 "7"" <NA> Vinyl 1
#> # … with 270 more rowsPo potrebi ih možete ponovno pridružiti izvornom skupu podataka.
Zaključak
Do srži knjižnice tidyverse uključuje mnogo korisnih paketa ujedinjenih zajedničkom filozofijom obrade podataka.
U ovom smo članku ispitali obitelj funkcija unnest_*(), koji su usmjereni na rad s izdvajanjem elemenata iz ugniježđenih popisa. Ovaj paket sadrži mnoge druge korisne značajke koje olakšavaju pretvaranje podataka prema konceptu Uredni podaci.
Izvor: www.habr.com