Enum serde_json::value::Value

pub enum Value {
    Null,
    Bool(bool),
    I64(i64),
    U64(u64),
    F64(f64),
    String(String),
    Array(Vec<Value>),
    Object(Map<String, Value>),
}

Represents a JSON value

Variants

Null

Represents a JSON null value

Bool(bool)

Represents a JSON Boolean

I64(i64)

Represents a JSON signed integer

U64(u64)

Represents a JSON unsigned integer

F64(f64)

Represents a JSON floating point number

String(String)

Represents a JSON string

Array(Vec<Value>)

Represents a JSON array

Object(Map<String, Value>)

Represents a JSON object

Methods

impl Value

pub fn find<'a>(&'a self, key: &str) -> Option<&'a Value>

If the Value is an Object, returns the value associated with the provided key. Otherwise, returns None.

pub fn find_path<'a>(&'a self, keys: &[&str]) -> Option<&'a Value>

Attempts to get a nested Value Object for each key in keys. If any key is found not to exist, find_path will return None. Otherwise, it will return the Value associated with the final key.

pub fn lookup<'a>(&'a self, path: &str) -> Option<&'a Value>

Deprecated: Use Value.pointer() and pointer syntax instead.

Looks up a value by path.

This is a convenience method that splits the path by '.' and then feeds the sequence of keys into the find_path method.

let obj: Value = json::from_str(r#"{"x": {"a": 1}}"#).unwrap();

assert!(obj.lookup("x.a").unwrap() == &Value::U64(1));

pub fn pointer<'a>(&'a self, pointer: &str) -> Option<&'a Value>

Looks up a value by a JSON Pointer.

JSON Pointer defines a string syntax for identifying a specific value within a JavaScript Object Notation (JSON) document.

A Pointer is a Unicode string with the reference tokens separated by /. Inside tokens / is replaced by ~1 and ~ is replaced by ~0. The addressed value is returned and if there is no such value None is returned.

For more information read RFC6901.

pub fn pointer_mut<'a>(&'a mut self, pointer: &str) -> Option<&'a mut Value>

Looks up a value by a JSON Pointer and returns a mutable reference to that value.

JSON Pointer defines a string syntax for identifying a specific value within a JavaScript Object Notation (JSON) document.

A Pointer is a Unicode string with the reference tokens separated by /. Inside tokens / is replaced by ~1 and ~ is replaced by ~0. The addressed value is returned and if there is no such value None is returned.

For more information read RFC6901.

Example of Use

extern crate serde_json;

use serde_json::Value;
use std::mem;

fn main() {
    let s = r#"{"x": 1.0, "y": 2.0}"#;
    let mut value: Value = serde_json::from_str(s).unwrap();

    // Check value using read-only pointer
    assert_eq!(value.pointer("/x"), Some(&Value::F64(1.0)));
    // Change value with direct assignment
    *value.pointer_mut("/x").unwrap() = Value::F64(1.5);
    // Check that new value was written
    assert_eq!(value.pointer("/x"), Some(&Value::F64(1.5)));

    // "Steal" ownership of a value. Can replace with any valid Value.
    let old_x = value.pointer_mut("/x").map(|x| mem::replace(x, Value::Null)).unwrap();
    assert_eq!(old_x, Value::F64(1.5));
    assert_eq!(value.pointer("/x").unwrap(), &Value::Null);
}

pub fn search<'a>(&'a self, key: &str) -> Option<&'a Value>

If the Value is an Object, performs a depth-first search until a value associated with the provided key is found. If no value is found or the Value is not an Object, returns None.

pub fn is_object(&self) -> bool

Returns true if the Value is an Object. Returns false otherwise.

pub fn as_object(&self) -> Option<&Map<String, Value>>

If the Value is an Object, returns the associated Map. Returns None otherwise.

pub fn as_object_mut(&mut self) -> Option<&mut Map<String, Value>>

If the Value is an Object, returns the associated mutable Map. Returns None otherwise.

pub fn is_array(&self) -> bool

Returns true if the Value is an Array. Returns false otherwise.

pub fn as_array(&self) -> Option<&Vec<Value>>

If the Value is an Array, returns the associated vector. Returns None otherwise.

pub fn as_array_mut(&mut self) -> Option<&mut Vec<Value>>

If the Value is an Array, returns the associated mutable vector. Returns None otherwise.

pub fn is_string(&self) -> bool

Returns true if the Value is a String. Returns false otherwise.

pub fn as_str(&self) -> Option<&str>

If the Value is a String, returns the associated str. Returns None otherwise.

pub fn is_number(&self) -> bool

Returns true if the Value is a Number. Returns false otherwise.

pub fn is_i64(&self) -> bool

Returns true if the Value is a i64. Returns false otherwise.

pub fn is_u64(&self) -> bool

Returns true if the Value is a u64. Returns false otherwise.

pub fn is_f64(&self) -> bool

Returns true if the Value is a f64. Returns false otherwise.

pub fn as_i64(&self) -> Option<i64>

If the Value is a number, return or cast it to a i64. Returns None otherwise.

pub fn as_u64(&self) -> Option<u64>

If the Value is a number, return or cast it to a u64. Returns None otherwise.

pub fn as_f64(&self) -> Option<f64>

If the Value is a number, return or cast it to a f64. Returns None otherwise.

pub fn is_boolean(&self) -> bool

Returns true if the Value is a Boolean. Returns false otherwise.

pub fn as_bool(&self) -> Option<bool>

If the Value is a Boolean, returns the associated bool. Returns None otherwise.

pub fn is_null(&self) -> bool

Returns true if the Value is a Null. Returns false otherwise.

pub fn as_null(&self) -> Option<()>

If the Value is a Null, returns (). Returns None otherwise.

Trait Implementations

impl Clone for Value

fn clone(&self) -> Value

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl PartialEq<Value> for Value

fn eq(&self, other: &Value) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Value) -> bool

This method tests for !=.

impl Display for Value

fn fmt(&self, f: &mut Formatter) -> Result

Serializes a json value into a string

impl Debug for Value

fn fmt(&self, f: &mut Formatter) -> Result

Serializes a json value into a string

impl FromStr for Value

type Err = Error

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Value, Error>

Parses a string s to return a value of this type.

impl Serialize for Value

fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where     S: Serializer,

Serializes this value into this serializer.

impl Deserialize for Value

fn deserialize<D>(deserializer: &mut D) -> Result<Value, D::Error> where     D: Deserializer,

Deserialize this value given this Deserializer.