R Language
JSON
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JSON naar / van R-objecten
Het jsonlite
pakket is een snelle JSON-parser en -generator die is geoptimaliseerd voor statistische gegevens en internet. De twee hoofdfuncties die worden gebruikt om JSON te lezen en te schrijven zijn fromJSON()
JSON fromJSON()
en toJSON()
en zijn ontworpen om te werken met vectors
, matrices
en data.frames
en JSON-stromen van het web.
Maak een JSON-array op basis van een vector en vice versa
library(jsonlite)
## vector to JSON
toJSON(c(1,2,3))
# [1,2,3]
fromJSON('[1,2,3]')
# [1] 1 2 3
Maak een JSON-array met een naam uit een lijst en vice versa
toJSON(list(myVec = c(1,2,3)))
# {"myVec":[1,2,3]}
fromJSON('{"myVec":[1,2,3]}')
# $myVec
# [1] 1 2 3
Meer complexe lijststructuren
## list structures
lst <- list(a = c(1,2,3),
b = list(letters[1:6]))
toJSON(lst)
# {"a":[1,2,3],"b":[["a","b","c","d","e","f"]]}
fromJSON('{"a":[1,2,3],"b":[["a","b","c","d","e","f"]]} ')
# $a
# [1] 1 2 3
#
# $b
# [,1] [,2] [,3] [,4] [,5] [,6]
# [1,] "a" "b" "c" "d" "e" "f"
Maak JSON van een data.frame
en vice versa
## converting a data.frame to JSON
df <- data.frame(id = seq_along(1:10),
val = letters[1:10])
toJSON(df)
# [{"id":1,"val":"a"},{"id":2,"val":"b"},{"id":3,"val":"c"},{"id":4,"val":"d"},{"id":5,"val":"e"},{"id":6,"val":"f"},{"id":7,"val":"g"},{"id":8,"val":"h"},{"id":9,"val":"i"},{"id":10,"val":"j"}]
## reading a JSON string
fromJSON('[{"id":1,"val":"a"},{"id":2,"val":"b"},{"id":3,"val":"c"},{"id":4,"val":"d"},{"id":5,"val":"e"},{"id":6,"val":"f"},{"id":7,"val":"g"},{"id":8,"val":"h"},{"id":9,"val":"i"},{"id":10,"val":"j"}]')
# id val
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
# 5 5 e
# 6 6 f
# 7 7 g
# 8 8 h
# 9 9 i
# 10 10 j
Lees JSON rechtstreeks van internet
## Reading JSON from URL
googleway_issues <- fromJSON("https://api.github.com/repos/SymbolixAU/googleway/issues")
googleway_issues$url
# [1] "https://api.github.com/repos/SymbolixAU/googleway/issues/20" "https://api.github.com/repos/SymbolixAU/googleway/issues/19"
# [3] "https://api.github.com/repos/SymbolixAU/googleway/issues/14" "https://api.github.com/repos/SymbolixAU/googleway/issues/11"
# [5] "https://api.github.com/repos/SymbolixAU/googleway/issues/9" "https://api.github.com/repos/SymbolixAU/googleway/issues/5"
# [7] "https://api.github.com/repos/SymbolixAU/googleway/issues/2"
Modified text is an extract of the original Stack Overflow Documentation
Licentie onder CC BY-SA 3.0
Niet aangesloten bij Stack Overflow