JSON Path Tokens
This information is from the website: http://goessner.net/articles/JsonPath/ and is placed here for convenience. For the GetJSONToken functions, the token string is a JSON path expression.
JSONPath expressions always refer to a JSON structure in the same way as XPath expression are used in combination with an XML document. Since a JSON structure is usually anonymous and doesn't necessarily have a "root member object" JSONPath assumes the abstract name $ assigned to the outer level object.
JSONPath expressions can use the dot–notation: $.store.book[0].title
or the bracket–notation: $['store']['book'][0]['title']
JSONPath allows the wildcard symbol * for member names and array indices. It borrows the descendant operator '..' Expressions of the underlying scripting language (<expr>) can be used as an alternative to explicit names or indices as in $.store.book[(@.length-1)].title
using the symbol '@' for the current object. Filter expressions are supported via the syntax ?(<boolean expr>) as in $.store.book[?(@.price < 10)].title
JSONPath |
Description |
$ |
the root object/element |
@ |
the current object/element |
. or [] |
child operator |
n/a |
parent operator |
.. |
recursive descent. JSONPath borrows this syntax from E4X. |
* |
wildcard. All objects/elements regardless their names. |
n/a |
attribute access. JSON structures don't have attributes. |
[] |
subscript operator. XPath uses it to iterate over element collections and for predicates. In Javascript and JSON it is the native array operator. |
[,] |
Union operator in XPath results in a combination of node sets. JSONPath allows alternate names or array indices as a set. |
[start:end:step] |
array slice operator borrowed from ES4. |
?() |
applies a filter (script) expression. |
() |
script expression, using the underlying script engine. |
|
|
JSONPath examples
Let's practice JSONPath expressions by some more examples. We start with a simple JSON structure built after an XML example representing a bookstore.
{ "store": {
"book": [
{ "category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": 8.95
},
{ "category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": 12.99
},
{ "category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": 8.99
},
{ "category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": 22.99
}
],
"bicycle": {
"color": "red",
"price": 19.95
}
}
}
JSONPath |
Result |
$.store.book[*].author |
the authors of all books in the store |
$..author |
all authors |
$.store.* |
all things in store, which are some books and a red bicycle. |
$.store..price |
the price of everything in the store. |
$..book[2] |
the third book |
$..book[(@.length-1)] |
the last book in order. |
$..book[0,1] |
the first two books |
$..book[?(@.isbn)] |
filter all books with isbn number |
$..book[?(@.price<10)] |
filter all books cheapier than 10 |
$..* |
all Elements in XML document. All members of JSON structure. |
Created with the Personal Edition of HelpNDoc: Easy EPub and documentation editor