fromJSON.RdThese functions are used to convert between JSON data and R objects. The toJSON and fromJSON
functions use a class based mapping, which follows conventions outlined in this paper: https://arxiv.org/abs/1403.2805 (also available as vignette).
fromJSON( txt, simplifyVector = TRUE, simplifyDataFrame = simplifyVector, simplifyMatrix = simplifyVector, flatten = FALSE, ... ) toJSON( x, dataframe = c("rows", "columns", "values"), matrix = c("rowmajor", "columnmajor"), Date = c("ISO8601", "epoch"), POSIXt = c("string", "ISO8601", "epoch", "mongo"), factor = c("string", "integer"), complex = c("string", "list"), raw = c("base64", "hex", "mongo", "int", "js"), null = c("list", "null"), na = c("null", "string"), auto_unbox = FALSE, digits = 4, pretty = FALSE, force = FALSE, ... )
| txt | a JSON string, URL or file |
|---|---|
| simplifyVector | coerce JSON arrays containing only primitives into an atomic vector |
| simplifyDataFrame | coerce JSON arrays containing only records (JSON objects) into a data frame |
| simplifyMatrix | coerce JSON arrays containing vectors of equal mode and dimension into matrix or array |
| flatten | automatically |
| ... | arguments passed on to class specific |
| x | the object to be encoded |
| dataframe | how to encode data.frame objects: must be one of 'rows', 'columns' or 'values' |
| matrix | how to encode matrices and higher dimensional arrays: must be one of 'rowmajor' or 'columnmajor'. |
| Date | how to encode Date objects: must be one of 'ISO8601' or 'epoch' |
| POSIXt | how to encode POSIXt (datetime) objects: must be one of 'string', 'ISO8601', 'epoch' or 'mongo' |
| factor | how to encode factor objects: must be one of 'string' or 'integer' |
| complex | how to encode complex numbers: must be one of 'string' or 'list' |
| raw | how to encode raw objects: must be one of 'base64', 'hex' or 'mongo' |
| null | how to encode NULL values within a list: must be one of 'null' or 'list' |
| na | how to print NA values: must be one of 'null' or 'string'. Defaults are class specific |
| auto_unbox | automatically |
| digits | max number of decimal digits to print for numeric values. Use |
| pretty | adds indentation whitespace to JSON output. Can be TRUE/FALSE or a number specifying the number of spaces to indent. See |
| force | unclass/skip objects of classes with no defined JSON mapping |
The toJSON and fromJSON functions are drop-in replacements for the identically named functions
in packages rjson and RJSONIO. Our implementation uses an alternative, somewhat more consistent mapping
between R objects and JSON strings.
The serializeJSON and unserializeJSON functions in this package use an
alternative system to convert between R objects and JSON, which supports more classes but is much more verbose.
A JSON string is always unicode, using UTF-8 by default, hence there is usually no need to escape any characters.
However, the JSON format does support escaping of unicode characters, which are encoded using a backslash followed by
a lower case "u" and 4 hex characters, for example: "Z\u00FCrich". The fromJSON function
will parse such escape sequences but it is usually preferable to encode unicode characters in JSON using native
UTF-8 rather than escape sequences.
Jeroen Ooms (2014). The jsonlite Package: A Practical and Consistent Mapping Between JSON Data and R Objects. arXiv:1403.2805. https://arxiv.org/abs/1403.2805
#> [ #> { #> "mpg": 21, #> "cyl": 6, #> "disp": 160, #> "hp": 110, #> "drat": 3.9, #> "wt": 2.62, #> "qsec": 16.46, #> "vs": 0, #> "am": 1, #> "gear": 4, #> "carb": 4, #> "_row": "Mazda RX4" #> }, #> { #> "mpg": 21, #> "cyl": 6, #> "disp": 160, #> "hp": 110, #> "drat": 3.9, #> "wt": 2.875, #> "qsec": 17.02, #> "vs": 0, #> "am": 1, #> "gear": 4, #> "carb": 4, #> "_row": "Mazda RX4 Wag" #> }, #> { #> "mpg": 22.8, #> "cyl": 4, #> "disp": 108, #> "hp": 93, #> "drat": 3.85, #> "wt": 2.32, #> "qsec": 18.61, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 1, #> "_row": "Datsun 710" #> }, #> { #> "mpg": 21.4, #> "cyl": 6, #> "disp": 258, #> "hp": 110, #> "drat": 3.08, #> "wt": 3.215, #> "qsec": 19.44, #> "vs": 1, #> "am": 0, #> "gear": 3, #> "carb": 1, #> "_row": "Hornet 4 Drive" #> }, #> { #> "mpg": 18.7, #> "cyl": 8, #> "disp": 360, #> "hp": 175, #> "drat": 3.15, #> "wt": 3.44, #> "qsec": 17.02, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 2, #> "_row": "Hornet Sportabout" #> }, #> { #> "mpg": 18.1, #> "cyl": 6, #> "disp": 225, #> "hp": 105, #> "drat": 2.76, #> "wt": 3.46, #> "qsec": 20.22, #> "vs": 1, #> "am": 0, #> "gear": 3, #> "carb": 1, #> "_row": "Valiant" #> }, #> { #> "mpg": 14.3, #> "cyl": 8, #> "disp": 360, #> "hp": 245, #> "drat": 3.21, #> "wt": 3.57, #> "qsec": 15.84, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 4, #> "_row": "Duster 360" #> }, #> { #> "mpg": 24.4, #> "cyl": 4, #> "disp": 146.7, #> "hp": 62, #> "drat": 3.69, #> "wt": 3.19, #> "qsec": 20, #> "vs": 1, #> "am": 0, #> "gear": 4, #> "carb": 2, #> "_row": "Merc 240D" #> }, #> { #> "mpg": 22.8, #> "cyl": 4, #> "disp": 140.8, #> "hp": 95, #> "drat": 3.92, #> "wt": 3.15, #> "qsec": 22.9, #> "vs": 1, #> "am": 0, #> "gear": 4, #> "carb": 2, #> "_row": "Merc 230" #> }, #> { #> "mpg": 19.2, #> "cyl": 6, #> "disp": 167.6, #> "hp": 123, #> "drat": 3.92, #> "wt": 3.44, #> "qsec": 18.3, #> "vs": 1, #> "am": 0, #> "gear": 4, #> "carb": 4, #> "_row": "Merc 280" #> }, #> { #> "mpg": 17.8, #> "cyl": 6, #> "disp": 167.6, #> "hp": 123, #> "drat": 3.92, #> "wt": 3.44, #> "qsec": 18.9, #> "vs": 1, #> "am": 0, #> "gear": 4, #> "carb": 4, #> "_row": "Merc 280C" #> }, #> { #> "mpg": 16.4, #> "cyl": 8, #> "disp": 275.8, #> "hp": 180, #> "drat": 3.07, #> "wt": 4.07, #> "qsec": 17.4, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 3, #> "_row": "Merc 450SE" #> }, #> { #> "mpg": 17.3, #> "cyl": 8, #> "disp": 275.8, #> "hp": 180, #> "drat": 3.07, #> "wt": 3.73, #> "qsec": 17.6, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 3, #> "_row": "Merc 450SL" #> }, #> { #> "mpg": 15.2, #> "cyl": 8, #> "disp": 275.8, #> "hp": 180, #> "drat": 3.07, #> "wt": 3.78, #> "qsec": 18, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 3, #> "_row": "Merc 450SLC" #> }, #> { #> "mpg": 10.4, #> "cyl": 8, #> "disp": 472, #> "hp": 205, #> "drat": 2.93, #> "wt": 5.25, #> "qsec": 17.98, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 4, #> "_row": "Cadillac Fleetwood" #> }, #> { #> "mpg": 10.4, #> "cyl": 8, #> "disp": 460, #> "hp": 215, #> "drat": 3, #> "wt": 5.424, #> "qsec": 17.82, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 4, #> "_row": "Lincoln Continental" #> }, #> { #> "mpg": 14.7, #> "cyl": 8, #> "disp": 440, #> "hp": 230, #> "drat": 3.23, #> "wt": 5.345, #> "qsec": 17.42, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 4, #> "_row": "Chrysler Imperial" #> }, #> { #> "mpg": 32.4, #> "cyl": 4, #> "disp": 78.7, #> "hp": 66, #> "drat": 4.08, #> "wt": 2.2, #> "qsec": 19.47, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 1, #> "_row": "Fiat 128" #> }, #> { #> "mpg": 30.4, #> "cyl": 4, #> "disp": 75.7, #> "hp": 52, #> "drat": 4.93, #> "wt": 1.615, #> "qsec": 18.52, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 2, #> "_row": "Honda Civic" #> }, #> { #> "mpg": 33.9, #> "cyl": 4, #> "disp": 71.1, #> "hp": 65, #> "drat": 4.22, #> "wt": 1.835, #> "qsec": 19.9, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 1, #> "_row": "Toyota Corolla" #> }, #> { #> "mpg": 21.5, #> "cyl": 4, #> "disp": 120.1, #> "hp": 97, #> "drat": 3.7, #> "wt": 2.465, #> "qsec": 20.01, #> "vs": 1, #> "am": 0, #> "gear": 3, #> "carb": 1, #> "_row": "Toyota Corona" #> }, #> { #> "mpg": 15.5, #> "cyl": 8, #> "disp": 318, #> "hp": 150, #> "drat": 2.76, #> "wt": 3.52, #> "qsec": 16.87, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 2, #> "_row": "Dodge Challenger" #> }, #> { #> "mpg": 15.2, #> "cyl": 8, #> "disp": 304, #> "hp": 150, #> "drat": 3.15, #> "wt": 3.435, #> "qsec": 17.3, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 2, #> "_row": "AMC Javelin" #> }, #> { #> "mpg": 13.3, #> "cyl": 8, #> "disp": 350, #> "hp": 245, #> "drat": 3.73, #> "wt": 3.84, #> "qsec": 15.41, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 4, #> "_row": "Camaro Z28" #> }, #> { #> "mpg": 19.2, #> "cyl": 8, #> "disp": 400, #> "hp": 175, #> "drat": 3.08, #> "wt": 3.845, #> "qsec": 17.05, #> "vs": 0, #> "am": 0, #> "gear": 3, #> "carb": 2, #> "_row": "Pontiac Firebird" #> }, #> { #> "mpg": 27.3, #> "cyl": 4, #> "disp": 79, #> "hp": 66, #> "drat": 4.08, #> "wt": 1.935, #> "qsec": 18.9, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 1, #> "_row": "Fiat X1-9" #> }, #> { #> "mpg": 26, #> "cyl": 4, #> "disp": 120.3, #> "hp": 91, #> "drat": 4.43, #> "wt": 2.14, #> "qsec": 16.7, #> "vs": 0, #> "am": 1, #> "gear": 5, #> "carb": 2, #> "_row": "Porsche 914-2" #> }, #> { #> "mpg": 30.4, #> "cyl": 4, #> "disp": 95.1, #> "hp": 113, #> "drat": 3.77, #> "wt": 1.513, #> "qsec": 16.9, #> "vs": 1, #> "am": 1, #> "gear": 5, #> "carb": 2, #> "_row": "Lotus Europa" #> }, #> { #> "mpg": 15.8, #> "cyl": 8, #> "disp": 351, #> "hp": 264, #> "drat": 4.22, #> "wt": 3.17, #> "qsec": 14.5, #> "vs": 0, #> "am": 1, #> "gear": 5, #> "carb": 4, #> "_row": "Ford Pantera L" #> }, #> { #> "mpg": 19.7, #> "cyl": 6, #> "disp": 145, #> "hp": 175, #> "drat": 3.62, #> "wt": 2.77, #> "qsec": 15.5, #> "vs": 0, #> "am": 1, #> "gear": 5, #> "carb": 6, #> "_row": "Ferrari Dino" #> }, #> { #> "mpg": 15, #> "cyl": 8, #> "disp": 301, #> "hp": 335, #> "drat": 3.54, #> "wt": 3.57, #> "qsec": 14.6, #> "vs": 0, #> "am": 1, #> "gear": 5, #> "carb": 8, #> "_row": "Maserati Bora" #> }, #> { #> "mpg": 21.4, #> "cyl": 4, #> "disp": 121, #> "hp": 109, #> "drat": 4.11, #> "wt": 2.78, #> "qsec": 18.6, #> "vs": 1, #> "am": 1, #> "gear": 4, #> "carb": 2, #> "_row": "Volvo 142E" #> } #> ]# Parse it back fromJSON(jsoncars)#> mpg cyl disp hp drat wt qsec vs am gear carb #> Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 #> Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 #> Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 #> Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 #> Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 #> Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 #> Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 #> Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 #> Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 #> Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 #> Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 #> Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3 #> Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3 #> Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3 #> Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4 #> Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4 #> Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4 #> Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 #> Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 #> Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 #> Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 #> Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2 #> AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 #> Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4 #> Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2 #> Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 #> Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 #> Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 #> Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4 #> Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 #> Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8 #> Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2# Parse escaped unicode fromJSON('{"city" : "Z\\u00FCrich"}')#> $city #> [1] "Zürich" #># Decimal vs significant digits toJSON(pi, digits=3)#> [3.142]#> [3.14]if (FALSE) { #retrieve data frame data1 <- fromJSON("https://api.github.com/users/hadley/orgs") names(data1) data1$login # Nested data frames: data2 <- fromJSON("https://api.github.com/users/hadley/repos") names(data2) names(data2$owner) data2$owner$login # Flatten the data into a regular non-nested dataframe names(flatten(data2)) # Flatten directly (more efficient): data3 <- fromJSON("https://api.github.com/users/hadley/repos", flatten = TRUE) identical(data3, flatten(data2)) }