Functions in JPath expressions

Some basic functions can be used in JPath expressions, such as using a function as part of a query.

The following table shows the basic functions that can be used in JPath expressions.
Table 1. Functions
Function Description
count(path) Returns the number of items at a specific path expression.
  • For an object, returns the number of members.
  • For an array, returns the number of array elements.
  • For a string, returns the string length.
base64_encode(expr) Returns the base64 encoded value of a specific expression.
base64_decode(expr) Returns the base64 decoded value of a specific expression.
url_encode(expr) Returns the url encoded value of a specific expression.
url_decode(expr) Returns the url decoded value of a specific expression.
min(path) Returns the minimum value from an array at a specific path expression.
max(path) Returns the maximum value from an array at a specific path expression.
time() Returns time in milliseconds since epoch.
New in V2 trunc(expr) Returns the truncated value of a specific number expression.
New in V2 round(expr) Returns the rounded value of a specific number expression.
New in V2 floor(expr) Returns the floor of a specific number expression.
New in V2 ceil(expr) Returns the ceiling of a specific number expression.
New in V2 random_number() Returns a random floating point number between 0.0 and 1.0.
New in V2 substring(expr, begin, end) Returns the substring of a specific expression.
New in V2 left(expr, length) Returns the left portion of a specific expression.
New in V2 right(expr, length) Returns the right portion of a specific expression.
New in V2 upper(expr) Returns the uppercase value of a specific expression.
New in V2 lower(expr) Returns the lowercase value of a specific expression.
New in V2 random_string(length) Returns a random string of Latin alphabetic characters (a-z, A-Z).
New in V2 empty(path) Returns true if the value at a specific path expression is empty.
New in V2 pad_left(expr, length, padValue) Returns the left-padded value of a specific expression.
New in V2 pad_right(expr, length, padValue) Returns the right-padded value of a specific expression.
New in V2 range(begin, end) Returns a range of numbers as an array.
New in V2 keys(path) Returns the keys of the object at a specific path expression.
New in V2 values(path) Returns the values of the object at a specific path expression.
New in V2 entries(path) Returns the entries of the object at a specific path expression.

The following table shows examples of basic functions that can be used in JPath expressions.

Table 2. Function examples
Example Description State Expression Result
Function in query Uses a function as part of a query. { "array": [ { "id": 1, "timestamp": 1186978597 }, { "id": 2, "timestamp": 1286978597 }, { "id": 3, "timestamp": 17586978597 } ] } /array[@timestamp > time()] [ { "id": 3, "timestamp": 17586978597 } ]
Find an event with the biggest timestamp Uses the max() function in combination with a generated array of numbers. { "array": [ { "id": 1, "timestamp": 1186978597 }, { "id": 2, "timestamp": 1286978597 }, { "id": 3, "timestamp": 17586978597 } ] } max(/array/timestamp) 17586978597