Enum serde_json::value::Value

pub enum Value {
    Null,
    Bool(bool),
    Number(Number),
    String(String),
    Array(Vec<Value>),
    Object(Map<String, Value>),
}

Represents any valid JSON value.

Variants

Null

Represents a JSON null value.

Bool(bool)

Represents a JSON boolean.

Number(Number)

Represents a JSON number, whether integer or floating point.

String(String)

Represents a JSON string.

Array(Vec<Value>)

Represents a JSON array.

Object(Map<String, Value>)

Represents a JSON object.

Methods

impl Value

fn get<I: Index>(&self, index: I) -> Option<&Value>

Index into a JSON array or map. A string index can be used to access a value in a map, and a usize index can be used to access an element of an array.

Returns None if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns None if the given key does not exist in the map or the given index is not within the bounds of the array.

let object = json!({ "A": 65, "B": 66, "C": 67 });
assert_eq!(*object.get("A").unwrap(), json!(65));

let array = json!([ "A", "B", "C" ]);
assert_eq!(*array.get(2).unwrap(), json!("C"));

assert_eq!(array.get("A"), None);

Square brackets can also be used to index into a value in a more concise way. This returns Value::Null in cases where get would have returned None.

let object = json!({
    "A": ["a", "á", "à"],
    "B": ["b", "b́"],
    "C": ["c", "ć", "ć̣", "ḉ"],
});
assert_eq!(object["B"][0], json!("b"));

assert_eq!(object["D"], json!(null));
assert_eq!(object[0]["x"]["y"]["z"], json!(null));

fn get_mut<I: Index>(&mut self, index: I) -> Option<&mut Value>

Mutably index into a JSON array or map. A string index can be used to access a value in a map, and a usize index can be used to access an element of an array.

Returns None if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns None if the given key does not exist in the map or the given index is not within the bounds of the array.

let mut object = json!({ "A": 65, "B": 66, "C": 67 });
*object.get_mut("A").unwrap() = json!(69);

let mut array = json!([ "A", "B", "C" ]);
*array.get_mut(2).unwrap() = json!("D");

fn is_object(&self) -> bool

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

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

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

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.

fn is_array(&self) -> bool

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

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

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

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

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

fn is_string(&self) -> bool

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

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

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

fn is_number(&self) -> bool

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

fn is_i64(&self) -> bool

Returns true if the Value is a number that can be represented by i64.

fn is_u64(&self) -> bool

Returns true if the Value is a number that can be represented by u64.

fn is_f64(&self) -> bool

Returns true if the Value is a number that can be represented by f64.

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

If the Value is a number, represent it as i64 if possible. Returns None otherwise.

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

If the Value is a number, represent it as u64 if possible. Returns None otherwise.

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

If the Value is a number, represent it as f64 if possible. Returns None otherwise.

fn is_boolean(&self) -> bool

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

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

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

fn is_null(&self) -> bool

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

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

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

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.

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(&1.0.into()));
    // Change value with direct assignment
    *value.pointer_mut("/x").unwrap() = 1.5.into();
    // Check that new value was written
    assert_eq!(value.pointer("/x"), Some(&1.5.into()));

    // "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, 1.5.into());
    assert_eq!(value.pointer("/x").unwrap(), &Value::Null);
}

Trait Implementations

impl Debug for Value

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

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 for Value

fn eq(&self, __arg_0: &Value) -> bool

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

fn ne(&self, __arg_0: &Value) -> bool

This method tests for !=.

impl<I> Index<I> for Value where I: Index

type Output = Value

The returned type after indexing

fn index(&self, index: I) -> &Value

Index into a serde_json::Value using the syntax value[0] or value["k"].

Returns Value::Null if the type of self does not match the type of the index, for example if the index is a string and self is an array or a number. Also returns Value::Null if the given key does not exist in the map or the given index is not within the bounds of the array.

impl From<i8> for Value

fn from(n: i8) -> Self

Performs the conversion.

impl From<i16> for Value

fn from(n: i16) -> Self

Performs the conversion.

impl From<i32> for Value

fn from(n: i32) -> Self

Performs the conversion.

impl From<i64> for Value

fn from(n: i64) -> Self

Performs the conversion.

impl From<isize> for Value

fn from(n: isize) -> Self

Performs the conversion.

impl From<u8> for Value

fn from(n: u8) -> Self

Performs the conversion.

impl From<u16> for Value

fn from(n: u16) -> Self

Performs the conversion.

impl From<u32> for Value

fn from(n: u32) -> Self

Performs the conversion.

impl From<u64> for Value

fn from(n: u64) -> Self

Performs the conversion.

impl From<usize> for Value

fn from(n: usize) -> Self

Performs the conversion.

impl From<f32> for Value

fn from(f: f32) -> Self

Performs the conversion.

impl From<f64> for Value

fn from(f: f64) -> Self

Performs the conversion.

impl Serialize for Value

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

Serialize this value into the given Serde serializer.

impl Deserialize for Value

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

Deserialize this value from the given Serde deserializer.

impl Display 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 Deserializer for Value

type Error = Error

The error type that can be returned if some error occurs during deserialization.

fn deserialize<V>(self, visitor: V) -> Result<V::Value, Error> where V: Visitor

Require the Deserializer to figure out how to drive the visitor based on what data type is in the input.

fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where V: Visitor

Hint that the Deserialize type is expecting an optional value.

fn deserialize_enum<V>(self,
                       _name: &str,
                       _variants: &'static [&'static str],
                       visitor: V)
                       -> Result<V::Value, Error> where V: Visitor

Hint that the Deserialize type is expecting an enum value with a particular name and possible variants.

fn deserialize_newtype_struct<V>(self,
                                 _name: &'static str,
                                 visitor: V)
                                 -> Result<V::Value, Self::Error> where V: Visitor

Hint that the Deserialize type is expecting a newtype struct with a particular name.

fn deserialize_bool<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a bool value.

fn deserialize_u8<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a u8 value.

fn deserialize_u16<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a u16 value.

fn deserialize_u32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a u32 value.

fn deserialize_u64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a u64 value.

fn deserialize_i8<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting an i8 value.

fn deserialize_i16<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting an i16 value.

fn deserialize_i32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting an i32 value.

fn deserialize_i64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting an i64 value.

fn deserialize_f32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a f32 value.

fn deserialize_f64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a f64 value.

fn deserialize_char<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a char value.

fn deserialize_str<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a string value and does not benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_string<__V>(self,
                           visitor: __V)
                           -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a string value and would benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_unit<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a unit value.

fn deserialize_seq<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a sequence of values.

fn deserialize_seq_fixed_size<__V>(self,
                                   _: usize,
                                   visitor: __V)
                                   -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a sequence of values and knows how many values there are without looking at the serialized data.

fn deserialize_bytes<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a byte array and does not benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_byte_buf<__V>(self,
                             visitor: __V)
                             -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a byte array and would benefit from taking ownership of buffered data owned by the Deserializer.

fn deserialize_map<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a map of key-value pairs.

fn deserialize_unit_struct<__V>(self,
                                _: &'static str,
                                visitor: __V)
                                -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a unit struct with a particular name.

fn deserialize_tuple_struct<__V>(self,
                                 _: &'static str,
                                 _: usize,
                                 visitor: __V)
                                 -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a tuple struct with a particular name and number of fields.

fn deserialize_struct<__V>(self,
                           _: &'static str,
                           _: &'static [&'static str],
                           visitor: __V)
                           -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a struct with a particular name and fields.

fn deserialize_struct_field<__V>(self,
                                 visitor: __V)
                                 -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting the name of a struct field.

fn deserialize_tuple<__V>(self,
                          _: usize,
                          visitor: __V)
                          -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type is expecting a tuple value with a particular number of elements.

fn deserialize_ignored_any<__V>(self,
                                visitor: __V)
                                -> Result<__V::Value, Self::Error> where __V: Visitor

Hint that the Deserialize type needs to deserialize a value whose type doesn't matter because it is ignored.