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RawJSON (.json)

Background & Context

    • MIME type: application/json.
    • Data interchange format.
    • RawJSON supports full JSON syntax but uses a specific interpretation.
    • RawJSON identifies JSON objects with Wolfram Language associations.
    • JSON is commonly used in web programming.
    • JSON is an acronym derived from JavaScript Object Notation.
    • JSON is based on a subset of the JavaScript programming language.
    • Plain text format.
    • JSON was developed in 2001.
    • JSON is published as RFC 4627.

Import & Export

Import Elements

  • General Import elements:
  • "Elements" list of elements and options available in this file
    "Summary"summary of the file
    "Rules"list of rules for all available elements
  • Data representation element:
  • "Data"contents of a JSON file as nested lists or associations
    "Dataset"contents of a JSON file as a Dataset
  • Import by default uses the "Data" element.
  • The "RawJSON" format identifies JSON objects of the form {field1:value1,field2:value2,…} with associations of the form <|"field1"->value1,"field2"->value2,…|> in the Wolfram Language.
  • "RawJSON" identifies JSON lists [e1,e2,…] with Wolfram Language lists {e1,e2,…}.
  • Strings in the Wolfram Language are represented in RawJSON as UTF-8 strings, escaped as required by the JSON standard.
  • Numbers where scientific notation is used are given in RawJSON in E notation.
  • The symbols True and False are represented in RawJSON as the values true and false.
  • The symbol Null is represented as the JSON value null.

Options

  • Export options:
  • "Compact"Falsewhether to omit line breaks and tabs
    "ConversionFunction"Nonefunction to apply for additional conversions
    "ConversionRules"{}rules to apply to override or add conversions
  • The setting for "ConversionRules" is used to replace subexpressions before built-in conversions are performed.
  • The setting for "ConversionFunction" is applied to subexpressions for which no built-in conversion is defined.
  • "Compact"->n includes line breaks and tabs up to indent level n.

Examples

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Basic Examples  (8)

Import a JSON list:

Wolfram Language code: ImportString["[1,2,3]", "JSON"]

Give a string consisting of a JSON object:

Wolfram Language code: "{\"x\":1, \"y\":2, \"z\":3}"

Importing this string as an association:

Wolfram Language code: ImportString[%, "RawJSON"]

Import a URL:

Wolfram Language code: Import["http://en.wikipedia.org/w/api.php?action=query&prop=links&titles=Wolfram%20Language&continue=&format=json", "RawJSON"]

Export an expression to a JSON string:

Wolfram Language code: ExportString[{1, 2, 3}, "RawJSON", "Compact" -> True]
Wolfram Language code: ExportString[<|"x" -> 1, "y" -> 2, "z" -> 3|>, "RawJSON", "Compact" -> True]

Export a list of chemical elements and their properties to a JSON file:

Wolfram Language code: Export["elements.json", <|"Hydrogen" -> <|"AtomicNumber" -> 1, "AtomicWeight" -> 1.00793|>, "Helium" -> <|"AtomicNumber" -> 4.00259, "AtomicWeight" -> 2|>, "Lithium" -> <|"AtomicNumber" -> 3, "AtomicWeight" -> 6.94141|>, "Beryllium" -> <|"AtomicNumber" -> 4, "AtomicWeight" -> 9.01218|>, "Boron" -> <|"AtomicNumber" -> 5, "AtomicWeight" -> 10.8086|>, "Carbon" -> <|"AtomicNumber" -> "6", "AtomicWeight" -> 12.0107|>|>, "RawJSON"]

Export to a string:

Wolfram Language code: ExportString[<|"Hydrogen" -> <|"AtomicNumber" -> 1, "AtomicWeight" -> 1.00793|>, "Helium" -> <|"AtomicNumber" -> 4.00259, "AtomicWeight" -> 2|>, "Lithium" -> <|"AtomicNumber" -> 3, "AtomicWeight" -> 6.94141|>, "Beryllium" -> <|"AtomicNumber" -> 4, "AtomicWeight" -> 9.01218|>, "Boron" -> <|"AtomicNumber" -> 5, "AtomicWeight" -> 10.8086|>, "Carbon" -> <|"AtomicNumber" -> "6", "AtomicWeight" -> 12.0107|>|>, "RawJSON"]

Use conversion function to format dates to ISO 8601:

Wolfram Language code: ExportString[ {<|"day" -> Yesterday, "T" -> "24.4"|>, <|"day" -> Now, "T" -> "23.1"|>}, "RawJSON" , "ConversionFunction" -> (DateString[#, {"ISODateTime", "ISOTimeZone"}]&)]

Use conversion rules to transform rules and quantities:

Wolfram Language code: ExportString[<|"files" -> {"file1" -> Quantity["1.2", "Kilobytes"], "file2" -> Quantity["5.7", "Megabytes"]}|>, "RawJSON", "ConversionRules" -> { Rule[file_, size_] :> <|"file" -> file, "size" -> size|>, Quantity[magnitude_, unit_] :> <|"magnitude" -> magnitude, "unit" -> unit|>}]

Control the output format with "Compact", to limit indentation:

Wolfram Language code: ExportString[<|"x" -> {{1, 2}, {3, 4}}, "y" -> {{Null}}|>, "RawJSON", "Compact" -> 1]

Scope  (1)

Create a compact string representation of a JSON file:

Wolfram Language code: ExportString[{"Hydrogen" -> {"AtomicNumber" -> 1, "AtomicWeight" -> 1.00793}, "Helium" -> {"AtomicNumber" -> 4.00259, "AtomicWeight" -> 2}, "Lithium" -> {"AtomicNumber" -> 3, "AtomicWeight" -> 6.94141}, "Beryllium" -> {"AtomicNumber" -> 4, "AtomicWeight" -> 9.01218}, "Boron" -> {"AtomicNumber" -> 5, "AtomicWeight" -> 10.8086}, "Carbon" -> {"AtomicNumber" -> "6", "AtomicWeight" -> 12.0107}}, "JSON", "Compact" -> True]

Import as an association:

Wolfram Language code: ImportString[%, "RawJSON"]

Import Elements  (2)

"Data"  (1)

Import a JSON file as nested associations:

Wolfram Language code: Import["http://en.wikipedia.org/w/api.php?action=query&prop=links&titles=Wolfram%20Language&continue=&format=json", {"RawJSON", "Data"}]

"Dataset"  (1)

Import a JSON file as a Dataset:

Wolfram Language code: Import["http://en.wikipedia.org/w/api.php?action=query&prop=links&titles=Wolfram%20Language&continue=&format=json", {"RawJSON", "Dataset"}]