[][src]Enum serde_json::Value

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

Represents any valid JSON value.

See the serde_json::value module documentation for usage examples.

Variants

Null

Represents a JSON null value.

This code runs with edition 2018
let v = json!(null);
Bool(bool)

Represents a JSON boolean.

This code runs with edition 2018
let v = json!(true);
Number(Number)

Represents a JSON number, whether integer or floating point.

This code runs with edition 2018
let v = json!(12.5);
String(String)

Represents a JSON string.

This code runs with edition 2018
let v = json!("a string");
Array(Vec<Value>)

Represents a JSON array.

This code runs with edition 2018
let v = json!(["an", "array"]);
Object(Map<String, Value>)

Represents a JSON object.

By default the map is backed by a BTreeMap. Enable the preserve_order feature of serde_json to use IndexMap instead, which preserves entries in the order they are inserted into the map. In particular, this allows JSON data to be deserialized into a Value and serialized to a string while retaining the order of map keys in the input.

This code runs with edition 2018
let v = json!({ "an": "object" });

Methods

impl Value[src]

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

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.

This code runs with edition 2018
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.

This code runs with edition 2018
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));

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

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.

This code runs with edition 2018
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");

pub fn is_object(&self) -> bool[src]

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

For any Value on which is_object returns true, as_object and as_object_mut are guaranteed to return the map representation of the object.

This code runs with edition 2018
let obj = json!({ "a": { "nested": true }, "b": ["an", "array"] });

assert!(obj.is_object());
assert!(obj["a"].is_object());

// array, not an object
assert!(!obj["b"].is_object());

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

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

This code runs with edition 2018
let v = json!({ "a": { "nested": true }, "b": ["an", "array"] });

// The length of `{"nested": true}` is 1 entry.
assert_eq!(v["a"].as_object().unwrap().len(), 1);

// The array `["an", "array"]` is not an object.
assert_eq!(v["b"].as_object(), None);

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

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

This code runs with edition 2018
let mut v = json!({ "a": { "nested": true } });

v["a"].as_object_mut().unwrap().clear();
assert_eq!(v, json!({ "a": {} }));

pub fn is_array(&self) -> bool[src]

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

For any Value on which is_array returns true, as_array and as_array_mut are guaranteed to return the vector representing the array.

This code runs with edition 2018
let obj = json!({ "a": ["an", "array"], "b": { "an": "object" } });

assert!(obj["a"].is_array());

// an object, not an array
assert!(!obj["b"].is_array());

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

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

This code runs with edition 2018
let v = json!({ "a": ["an", "array"], "b": { "an": "object" } });

// The length of `["an", "array"]` is 2 elements.
assert_eq!(v["a"].as_array().unwrap().len(), 2);

// The object `{"an": "object"}` is not an array.
assert_eq!(v["b"].as_array(), None);

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

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

This code runs with edition 2018
let mut v = json!({ "a": ["an", "array"] });

v["a"].as_array_mut().unwrap().clear();
assert_eq!(v, json!({ "a": [] }));

pub fn is_string(&self) -> bool[src]

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

For any Value on which is_string returns true, as_str is guaranteed to return the string slice.

This code runs with edition 2018
let v = json!({ "a": "some string", "b": false });

assert!(v["a"].is_string());

// The boolean `false` is not a string.
assert!(!v["b"].is_string());

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

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

This code runs with edition 2018
let v = json!({ "a": "some string", "b": false });

assert_eq!(v["a"].as_str(), Some("some string"));

// The boolean `false` is not a string.
assert_eq!(v["b"].as_str(), None);

// JSON values are printed in JSON representation, so strings are in quotes.
//
//    The value is: "some string"
println!("The value is: {}", v["a"]);

// Rust strings are printed without quotes.
//
//    The value is: some string
println!("The value is: {}", v["a"].as_str().unwrap());

pub fn is_number(&self) -> bool[src]

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

This code runs with edition 2018
let v = json!({ "a": 1, "b": "2" });

assert!(v["a"].is_number());

// The string `"2"` is a string, not a number.
assert!(!v["b"].is_number());

pub fn is_i64(&self) -> bool[src]

Returns true if the Value is an integer between i64::MIN and i64::MAX.

For any Value on which is_i64 returns true, as_i64 is guaranteed to return the integer value.

This code runs with edition 2018
let big = i64::max_value() as u64 + 10;
let v = json!({ "a": 64, "b": big, "c": 256.0 });

assert!(v["a"].is_i64());

// Greater than i64::MAX.
assert!(!v["b"].is_i64());

// Numbers with a decimal point are not considered integers.
assert!(!v["c"].is_i64());

pub fn is_u64(&self) -> bool[src]

Returns true if the Value is an integer between zero and u64::MAX.

For any Value on which is_u64 returns true, as_u64 is guaranteed to return the integer value.

This code runs with edition 2018
let v = json!({ "a": 64, "b": -64, "c": 256.0 });

assert!(v["a"].is_u64());

// Negative integer.
assert!(!v["b"].is_u64());

// Numbers with a decimal point are not considered integers.
assert!(!v["c"].is_u64());

pub fn is_f64(&self) -> bool[src]

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

For any Value on which is_f64 returns true, as_f64 is guaranteed to return the floating point value.

Currently this function returns true if and only if both is_i64 and is_u64 return false but this is not a guarantee in the future.

This code runs with edition 2018
let v = json!({ "a": 256.0, "b": 64, "c": -64 });

assert!(v["a"].is_f64());

// Integers.
assert!(!v["b"].is_f64());
assert!(!v["c"].is_f64());

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

If the Value is an integer, represent it as i64 if possible. Returns None otherwise.

This code runs with edition 2018
let big = i64::max_value() as u64 + 10;
let v = json!({ "a": 64, "b": big, "c": 256.0 });

assert_eq!(v["a"].as_i64(), Some(64));
assert_eq!(v["b"].as_i64(), None);
assert_eq!(v["c"].as_i64(), None);

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

If the Value is an integer, represent it as u64 if possible. Returns None otherwise.

This code runs with edition 2018
let v = json!({ "a": 64, "b": -64, "c": 256.0 });

assert_eq!(v["a"].as_u64(), Some(64));
assert_eq!(v["b"].as_u64(), None);
assert_eq!(v["c"].as_u64(), None);

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

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

This code runs with edition 2018
let v = json!({ "a": 256.0, "b": 64, "c": -64 });

assert_eq!(v["a"].as_f64(), Some(256.0));
assert_eq!(v["b"].as_f64(), Some(64.0));
assert_eq!(v["c"].as_f64(), Some(-64.0));

pub fn is_boolean(&self) -> bool[src]

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

For any Value on which is_boolean returns true, as_bool is guaranteed to return the boolean value.

This code runs with edition 2018
let v = json!({ "a": false, "b": "false" });

assert!(v["a"].is_boolean());

// The string `"false"` is a string, not a boolean.
assert!(!v["b"].is_boolean());

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

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

This code runs with edition 2018
let v = json!({ "a": false, "b": "false" });

assert_eq!(v["a"].as_bool(), Some(false));

// The string `"false"` is a string, not a boolean.
assert_eq!(v["b"].as_bool(), None);

pub fn is_null(&self) -> bool[src]

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

For any Value on which is_null returns true, as_null is guaranteed to return Some(()).

This code runs with edition 2018
let v = json!({ "a": null, "b": false });

assert!(v["a"].is_null());

// The boolean `false` is not null.
assert!(!v["b"].is_null());

pub fn as_null(&self) -> Option<()>[src]

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

This code runs with edition 2018
let v = json!({ "a": null, "b": false });

assert_eq!(v["a"].as_null(), Some(()));

// The boolean `false` is not null.
assert_eq!(v["b"].as_null(), None);

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

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.

Examples

This code runs with edition 2018
let data = json!({
    "x": {
        "y": ["z", "zz"]
    }
});

assert_eq!(data.pointer("/x/y/1").unwrap(), &json!("zz"));
assert_eq!(data.pointer("/a/b/c"), None);

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

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

This code runs with edition 2018
use serde_json::Value;

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

pub fn take(&mut self) -> Value[src]

Takes the value out of the Value, leaving a Null in its place.

This code runs with edition 2018
let mut v = json!({ "x": "y" });
assert_eq!(v["x"].take(), json!("y"));
assert_eq!(v, json!({ "x": null }));

Trait Implementations

impl PartialEq<Value> for Value[src]

impl PartialEq<str> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl<'a> PartialEq<&'a str> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<Value> for str[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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impl<'a> PartialEq<Value> for &'a str[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<String> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for String[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<i8> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for i8[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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impl<'a> PartialEq<i8> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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impl<'a> PartialEq<i8> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<i16> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for i16[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<i16> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<i16> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<i32> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<Value> for i32[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<i32> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<i32> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<i64> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for i64[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<i64> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<i64> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<isize> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for isize[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<isize> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<isize> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<u8> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for u8[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<u8> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<u8> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<u16> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<Value> for u16[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl<'a> PartialEq<u16> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl<'a> PartialEq<u16> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<u32> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl PartialEq<Value> for u32[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<u32> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<u32> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<u64> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<Value> for u64[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<u64> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<u64> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<usize> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<Value> for usize[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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impl<'a> PartialEq<usize> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<usize> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<f32> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl PartialEq<Value> for f32[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
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This method tests for !=.

impl<'a> PartialEq<f32> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<f32> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<f64> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<Value> for f64[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<f64> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<f64> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<bool> for Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl PartialEq<Value> for bool[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<bool> for &'a Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl<'a> PartialEq<bool> for &'a mut Value[src]

#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0
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This method tests for !=.

impl Default for Value[src]

The default value is Value::Null.

This is useful for handling omitted Value fields when deserializing.

Examples

This code runs with edition 2018
use serde_json::Value;

#[derive(Deserialize)]
struct Settings {
    level: i32,
    #[serde(default)]
    extras: Value,
}

let data = r#" { "level": 42 } "#;
let s: Settings = serde_json::from_str(data)?;

assert_eq!(s.level, 42);
assert_eq!(s.extras, Value::Null);

impl Clone for Value[src]

fn clone_from(&mut self, source: &Self)
1.0.0
[src]

Performs copy-assignment from source. Read more

impl From<i8> for Value[src]

impl From<i16> for Value[src]

impl From<i32> for Value[src]

impl From<i64> for Value[src]

impl From<isize> for Value[src]

impl From<u8> for Value[src]

impl From<u16> for Value[src]

impl From<u32> for Value[src]

impl From<u64> for Value[src]

impl From<usize> for Value[src]

impl From<f32> for Value[src]

fn from(f: f32) -> Self[src]

Convert 32-bit floating point number to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let f: f32 = 13.37;
let x: Value = f.into();

impl From<f64> for Value[src]

fn from(f: f64) -> Self[src]

Convert 64-bit floating point number to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let f: f64 = 13.37;
let x: Value = f.into();

impl From<bool> for Value[src]

fn from(f: bool) -> Self[src]

Convert boolean to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let b = false;
let x: Value = b.into();

impl From<String> for Value[src]

fn from(f: String) -> Self[src]

Convert String to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let s: String = "lorem".to_string();
let x: Value = s.into();

impl<'a> From<&'a str> for Value[src]

fn from(f: &str) -> Self[src]

Convert string slice to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let s: &str = "lorem";
let x: Value = s.into();

impl<'a> From<Cow<'a, str>> for Value[src]

fn from(f: Cow<'a, str>) -> Self[src]

Convert copy-on-write string to Value

Examples

This code runs with edition 2018
use serde_json::Value;
use std::borrow::Cow;

let s: Cow<str> = Cow::Borrowed("lorem");
let x: Value = s.into();
This code runs with edition 2018
use serde_json::Value;
use std::borrow::Cow;

let s: Cow<str> = Cow::Owned("lorem".to_string());
let x: Value = s.into();

impl From<Map<String, Value>> for Value[src]

fn from(f: Map<String, Value>) -> Self[src]

Convert map (with string keys) to Value

Examples

This code runs with edition 2018
use serde_json::{Map, Value};

let mut m = Map::new();
m.insert("Lorem".to_string(), "ipsum".into());
let x: Value = m.into();

impl<T: Into<Value>> From<Vec<T>> for Value[src]

fn from(f: Vec<T>) -> Self[src]

Convert a Vec to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let v = vec!["lorem", "ipsum", "dolor"];
let x: Value = v.into();

impl<'a, T: Clone + Into<Value>> From<&'a [T]> for Value[src]

fn from(f: &'a [T]) -> Self[src]

Convert a slice to Value

Examples

This code runs with edition 2018
use serde_json::Value;

let v: &[&str] = &["lorem", "ipsum", "dolor"];
let x: Value = v.into();

impl Debug for Value[src]

impl Display for Value[src]

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

Display a JSON value as a string.

This code runs with edition 2018
let json = json!({ "city": "London", "street": "10 Downing Street" });

// Compact format:
//
// {"city":"London","street":"10 Downing Street"}
let compact = format!("{}", json);
assert_eq!(compact,
    "{\"city\":\"London\",\"street\":\"10 Downing Street\"}");

// Pretty format:
//
// {
//   "city": "London",
//   "street": "10 Downing Street"
// }
let pretty = format!("{:#}", json);
assert_eq!(pretty,
    "{\n  \"city\": \"London\",\n  \"street\": \"10 Downing Street\"\n}");

impl<I> Index<I> for Value where
    I: Index
[src]

type Output = Value

The returned type after indexing.

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

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.

For retrieving deeply nested values, you should have a look at the Value::pointer method.

Examples

This code runs with edition 2018
let data = json!({
    "x": {
        "y": ["z", "zz"]
    }
});

assert_eq!(data["x"]["y"], json!(["z", "zz"]));
assert_eq!(data["x"]["y"][0], json!("z"));

assert_eq!(data["a"], json!(null)); // returns null for undefined values
assert_eq!(data["a"]["b"], json!(null)); // does not panic

impl<I> IndexMut<I> for Value where
    I: Index
[src]

fn index_mut(&mut self, index: I) -> &mut Value[src]

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

If the index is a number, the value must be an array of length bigger than the index. Indexing into a value that is not an array or an array that is too small will panic.

If the index is a string, the value must be an object or null which is treated like an empty object. If the key is not already present in the object, it will be inserted with a value of null. Indexing into a value that is neither an object nor null will panic.

Examples

This code runs with edition 2018
let mut data = json!({ "x": 0 });

// replace an existing key
data["x"] = json!(1);

// insert a new key
data["y"] = json!([false, false, false]);

// replace an array value
data["y"][0] = json!(true);

// inserted a deeply nested key
data["a"]["b"]["c"]["d"] = json!(true);

println!("{}", data);

impl<T: Into<Value>> FromIterator<T> for Value[src]

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self[src]

Convert an iteratable type to a Value

Examples

This code runs with edition 2018
use serde_json::Value;

let v = std::iter::repeat(42).take(5);
let x: Value = v.collect();
This code runs with edition 2018
use serde_json::Value;

let v: Vec<_> = vec!["lorem", "ipsum", "dolor"];
let x: Value = v.into_iter().collect();
This code runs with edition 2018
use std::iter::FromIterator;
use serde_json::Value;

let x: Value = Value::from_iter(vec!["lorem", "ipsum", "dolor"]);

impl FromStr for Value[src]

type Err = Error

The associated error which can be returned from parsing.

impl Serialize for Value[src]

impl<'de> Deserializer<'de> for Value[src]

type Error = Error

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

fn is_human_readable(&self) -> bool[src]

Determine whether Deserialize implementations should expect to deserialize their human-readable form. Read more

impl<'de> Deserializer<'de> for &'de Value[src]

type Error = Error

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

fn is_human_readable(&self) -> bool[src]

Determine whether Deserialize implementations should expect to deserialize their human-readable form. Read more

impl<'de> Deserialize<'de> for Value[src]

Auto Trait Implementations

impl Send for Value

impl Sync for Value

Blanket Implementations

impl<T> ToString for T where
    T: Display + ?Sized
[src]

impl<T> From for T[src]

impl<T, U> Into for T where
    U: From<T>, 
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

impl<T, U> TryFrom for T where
    T: From<U>, 
[src]

type Error = !

🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

impl<T> Borrow for T where
    T: ?Sized
[src]

impl<T> BorrowMut for T where
    T: ?Sized
[src]

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

🔬 This is a nightly-only experimental API. (try_from)

The type returned in the event of a conversion error.

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> DeserializeOwned for T where
    T: Deserialize<'de>, 
[src]