Enum serde_json::Value
source · [−]pub enum Value {
Null,
Bool(bool),
Number(Number),
String(String),
Array(Vec<Value>),
Object(Map<String, Value>),
}
Expand description
Represents any valid JSON value.
See the serde_json::value
module documentation for usage examples.
Variants
Null
Represents a JSON null value.
let v = json!(null);
Bool(bool)
Represents a JSON boolean.
let v = json!(true);
Number(Number)
Represents a JSON number, whether integer or floating point.
let v = json!(12.5);
String(String)
Represents a JSON string.
let v = json!("a string");
Array(Vec<Value>)
Represents a JSON array.
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.
let v = json!({ "an": "object" });
Implementations
sourceimpl Value
impl Value
sourcepub fn get<I: Index>(&self, index: I) -> Option<&Value>
pub 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));
sourcepub fn get_mut<I: Index>(&mut self, index: I) -> Option<&mut Value>
pub 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");
sourcepub fn is_object(&self) -> bool
pub fn is_object(&self) -> bool
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.
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());
sourcepub fn as_object(&self) -> Option<&Map<String, Value>>
pub fn as_object(&self) -> Option<&Map<String, Value>>
If the Value
is an Object, returns the associated Map. Returns None
otherwise.
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);
sourcepub fn as_object_mut(&mut self) -> Option<&mut Map<String, Value>>
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.
let mut v = json!({ "a": { "nested": true } });
v["a"].as_object_mut().unwrap().clear();
assert_eq!(v, json!({ "a": {} }));
sourcepub fn is_array(&self) -> bool
pub fn is_array(&self) -> bool
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.
let obj = json!({ "a": ["an", "array"], "b": { "an": "object" } });
assert!(obj["a"].is_array());
// an object, not an array
assert!(!obj["b"].is_array());
sourcepub fn as_array(&self) -> Option<&Vec<Value>>
pub fn as_array(&self) -> Option<&Vec<Value>>
If the Value
is an Array, returns the associated vector. Returns None
otherwise.
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);
sourcepub fn as_array_mut(&mut self) -> Option<&mut Vec<Value>>
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.
let mut v = json!({ "a": ["an", "array"] });
v["a"].as_array_mut().unwrap().clear();
assert_eq!(v, json!({ "a": [] }));
sourcepub fn is_string(&self) -> bool
pub fn is_string(&self) -> bool
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.
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());
sourcepub fn as_str(&self) -> Option<&str>
pub fn as_str(&self) -> Option<&str>
If the Value
is a String, returns the associated str. Returns None
otherwise.
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());
sourcepub fn is_number(&self) -> bool
pub fn is_number(&self) -> bool
Returns true if the Value
is a Number. Returns false otherwise.
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());
sourcepub fn is_i64(&self) -> bool
pub fn is_i64(&self) -> bool
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.
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());
sourcepub fn is_u64(&self) -> bool
pub fn is_u64(&self) -> bool
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.
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());
sourcepub fn is_f64(&self) -> bool
pub fn is_f64(&self) -> bool
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.
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());
sourcepub fn as_i64(&self) -> Option<i64>
pub fn as_i64(&self) -> Option<i64>
If the Value
is an integer, represent it as i64 if possible. Returns
None otherwise.
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);
sourcepub fn as_u64(&self) -> Option<u64>
pub fn as_u64(&self) -> Option<u64>
If the Value
is an integer, represent it as u64 if possible. Returns
None otherwise.
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);
sourcepub fn as_f64(&self) -> Option<f64>
pub fn as_f64(&self) -> Option<f64>
If the Value
is a number, represent it as f64 if possible. Returns
None otherwise.
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));
sourcepub fn is_boolean(&self) -> bool
pub fn is_boolean(&self) -> bool
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.
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());
sourcepub fn as_bool(&self) -> Option<bool>
pub fn as_bool(&self) -> Option<bool>
If the Value
is a Boolean, returns the associated bool. Returns None
otherwise.
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);
sourcepub fn is_null(&self) -> bool
pub fn is_null(&self) -> bool
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(())
.
let v = json!({ "a": null, "b": false });
assert!(v["a"].is_null());
// The boolean `false` is not null.
assert!(!v["b"].is_null());
sourcepub fn as_null(&self) -> Option<()>
pub fn as_null(&self) -> Option<()>
If the Value
is a Null, returns (). Returns None otherwise.
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);
sourcepub fn pointer(&self, pointer: &str) -> Option<&Value>
pub fn pointer(&self, pointer: &str) -> Option<&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.
Examples
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);
sourcepub fn pointer_mut(&mut self, pointer: &str) -> Option<&mut Value>
pub fn pointer_mut(&mut self, pointer: &str) -> Option<&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
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()));
// Or change the value only if it exists
value.pointer_mut("/x").map(|v| *v = 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);
}
Trait Implementations
sourceimpl Default for Value
impl Default for Value
The default value is Value::Null
.
This is useful for handling omitted Value
fields when deserializing.
Examples
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);
sourceimpl<'de> Deserialize<'de> for Value
impl<'de> Deserialize<'de> for Value
sourcefn deserialize<D>(deserializer: D) -> Result<Value, D::Error> where
D: Deserializer<'de>,
fn deserialize<D>(deserializer: D) -> Result<Value, D::Error> where
D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
sourceimpl<'de> Deserializer<'de> for Value
impl<'de> Deserializer<'de> for Value
type Error = Error
type Error = Error
The error type that can be returned if some error occurs during deserialization. Read more
sourcefn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Require the Deserializer
to figure out how to drive the visitor based
on what data type is in the input. Read more
sourcefn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i8
value.
sourcefn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i16
value.
sourcefn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i32
value.
sourcefn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i64
value.
sourcefn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u8
value.
sourcefn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u16
value.
sourcefn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u32
value.
sourcefn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u64
value.
sourcefn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a f32
value.
sourcefn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a f64
value.
sourcefn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i128
value. Read more
sourcefn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an u128
value. Read more
sourcefn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an optional value. Read more
sourcefn deserialize_enum<V>(
self,
_name: &str,
_variants: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_enum<V>(
self,
_name: &str,
_variants: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an enum value with a
particular name and possible variants. Read more
sourcefn deserialize_newtype_struct<V>(
self,
name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_newtype_struct<V>(
self,
name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a newtype struct with a
particular name. Read more
sourcefn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a bool
value.
sourcefn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a char
value.
sourcefn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a string value and does
not benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a string value and would
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a byte array and does not
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a byte array and would
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a unit value.
sourcefn deserialize_unit_struct<V>(
self,
_name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_unit_struct<V>(
self,
_name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a unit struct with a
particular name. Read more
sourcefn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a sequence of values.
sourcefn deserialize_tuple<V>(
self,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_tuple<V>(
self,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a sequence of values and
knows how many values there are without looking at the serialized data. Read more
sourcefn deserialize_tuple_struct<V>(
self,
_name: &'static str,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_tuple_struct<V>(
self,
_name: &'static str,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a tuple struct with a
particular name and number of fields. Read more
sourcefn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a map of key-value pairs.
sourcefn deserialize_struct<V>(
self,
_name: &'static str,
_fields: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_struct<V>(
self,
_name: &'static str,
_fields: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a struct with a particular
name and fields. Read more
sourcefn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting the name of a struct
field or the discriminant of an enum variant. Read more
sourcefn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type needs to deserialize a value whose type
doesn’t matter because it is ignored. Read more
sourcefn is_human_readable(&self) -> bool
fn is_human_readable(&self) -> bool
Determine whether Deserialize
implementations should expect to
deserialize their human-readable form. Read more
sourceimpl<'de> Deserializer<'de> for &'de Value
impl<'de> Deserializer<'de> for &'de Value
type Error = Error
type Error = Error
The error type that can be returned if some error occurs during deserialization. Read more
sourcefn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Require the Deserializer
to figure out how to drive the visitor based
on what data type is in the input. Read more
sourcefn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i8
value.
sourcefn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i16
value.
sourcefn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i32
value.
sourcefn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i64
value.
sourcefn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u8
value.
sourcefn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u16
value.
sourcefn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u32
value.
sourcefn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a u64
value.
sourcefn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a f32
value.
sourcefn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a f64
value.
sourcefn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an i128
value. Read more
sourcefn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an u128
value. Read more
sourcefn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an optional value. Read more
sourcefn deserialize_enum<V>(
self,
_name: &str,
_variants: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_enum<V>(
self,
_name: &str,
_variants: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting an enum value with a
particular name and possible variants. Read more
sourcefn deserialize_newtype_struct<V>(
self,
name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_newtype_struct<V>(
self,
name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a newtype struct with a
particular name. Read more
sourcefn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a bool
value.
sourcefn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a char
value.
sourcefn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a string value and does
not benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a string value and would
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a byte array and does not
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a byte array and would
benefit from taking ownership of buffered data owned by the
Deserializer
. Read more
sourcefn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a unit value.
sourcefn deserialize_unit_struct<V>(
self,
_name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_unit_struct<V>(
self,
_name: &'static str,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a unit struct with a
particular name. Read more
sourcefn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a sequence of values.
sourcefn deserialize_tuple<V>(
self,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_tuple<V>(
self,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a sequence of values and
knows how many values there are without looking at the serialized data. Read more
sourcefn deserialize_tuple_struct<V>(
self,
_name: &'static str,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_tuple_struct<V>(
self,
_name: &'static str,
_len: usize,
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a tuple struct with a
particular name and number of fields. Read more
sourcefn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a map of key-value pairs.
sourcefn deserialize_struct<V>(
self,
_name: &'static str,
_fields: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_struct<V>(
self,
_name: &'static str,
_fields: &'static [&'static str],
visitor: V
) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting a struct with a particular
name and fields. Read more
sourcefn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type is expecting the name of a struct
field or the discriminant of an enum variant. Read more
sourcefn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Error> where
V: Visitor<'de>,
Hint that the Deserialize
type needs to deserialize a value whose type
doesn’t matter because it is ignored. Read more
sourcefn is_human_readable(&self) -> bool
fn is_human_readable(&self) -> bool
Determine whether Deserialize
implementations should expect to
deserialize their human-readable form. Read more
sourceimpl Display for Value
impl Display for Value
sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Display a JSON value as a string.
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}");
sourceimpl<'a> From<Cow<'a, str>> for Value
impl<'a> From<Cow<'a, str>> for Value
sourcefn from(f: Cow<'a, str>) -> Self
fn from(f: Cow<'a, str>) -> Self
Convert copy-on-write string to Value
Examples
use serde_json::Value;
use std::borrow::Cow;
let s: Cow<str> = Cow::Borrowed("lorem");
let x: Value = s.into();
use serde_json::Value;
use std::borrow::Cow;
let s: Cow<str> = Cow::Owned("lorem".to_string());
let x: Value = s.into();
sourceimpl<T: Into<Value>> FromIterator<T> for Value
impl<T: Into<Value>> FromIterator<T> for Value
sourcefn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self
Convert an iteratable type to a Value
Examples
use serde_json::Value;
let v = std::iter::repeat(42).take(5);
let x: Value = v.collect();
use serde_json::Value;
let v: Vec<_> = vec!["lorem", "ipsum", "dolor"];
let x: Value = v.into_iter().collect();
use std::iter::FromIterator;
use serde_json::Value;
let x: Value = Value::from_iter(vec!["lorem", "ipsum", "dolor"]);
sourceimpl<I> Index<I> for Value where
I: Index,
impl<I> Index<I> for Value where
I: Index,
sourcefn index(&self, index: I) -> &Value
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.
For retrieving deeply nested values, you should have a look at the
Value::pointer
method.
Examples
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
sourceimpl<I> IndexMut<I> for Value where
I: Index,
impl<I> IndexMut<I> for Value where
I: Index,
sourcefn index_mut(&mut self, index: I) -> &mut Value
fn index_mut(&mut self, index: I) -> &mut Value
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
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);
sourceimpl<'de> IntoDeserializer<'de, Error> for Value
impl<'de> IntoDeserializer<'de, Error> for Value
type Deserializer = Self
type Deserializer = Self
The type of the deserializer being converted into.
sourcefn into_deserializer(self) -> Self::Deserializer
fn into_deserializer(self) -> Self::Deserializer
Convert this value into a deserializer.
impl Eq for Value
impl StructuralEq for Value
impl StructuralPartialEq for Value
Auto Trait Implementations
impl RefUnwindSafe for Value
impl Send for Value
impl Sync for Value
impl Unpin for Value
impl UnwindSafe for Value
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more