| de.rs |
|
39166 |
| from.rs |
|
6188 |
| index.rs |
|
8782 |
| mod.rs |
The Value enum, a loosely typed way of representing any valid JSON value.
# Constructing JSON
Serde JSON provides a [`json!` macro][macro] to build `serde_json::Value`
objects with very natural JSON syntax.
```
use serde_json::json;
fn main() {
// The type of `john` is `serde_json::Value`
let john = json!({
"name": "John Doe",
"age": 43,
"phones": [
"+44 1234567",
"+44 2345678"
]
});
println!("first phone number: {}", john["phones"][0]);
// Convert to a string of JSON and print it out
println!("{}", john.to_string());
}
```
The `Value::to_string()` function converts a `serde_json::Value` into a
`String` of JSON text.
One neat thing about the `json!` macro is that variables and expressions can
be interpolated directly into the JSON value as you are building it. Serde
will check at compile time that the value you are interpolating is able to
be represented as JSON.
```
# use serde_json::json;
#
# fn random_phone() -> u16 { 0 }
#
let full_name = "John Doe";
let age_last_year = 42;
// The type of `john` is `serde_json::Value`
let john = json!({
"name": full_name,
"age": age_last_year + 1,
"phones": [
format!("+44 {}", random_phone())
]
});
```
A string of JSON data can be parsed into a `serde_json::Value` by the
[`serde_json::from_str`][from_str] function. There is also
[`from_slice`][from_slice] for parsing from a byte slice `&[u8]` and
[`from_reader`][from_reader] for parsing from any `io::Read` like a File or
a TCP stream.
```
use serde_json::{json, Value, Error};
fn untyped_example() -> Result<(), Error> {
// Some JSON input data as a &str. Maybe this comes from the user.
let data = r#"
{
"name": "John Doe",
"age": 43,
"phones": [
"+44 1234567",
"+44 2345678"
]
}"#;
// Parse the string of data into serde_json::Value.
let v: Value = serde_json::from_str(data)?;
// Access parts of the data by indexing with square brackets.
println!("Please call {} at the number {}", v["name"], v["phones"][0]);
Ok(())
}
#
# untyped_example().unwrap();
```
[macro]: crate::json
[from_str]: crate::de::from_str
[from_slice]: crate::de::from_slice
[from_reader]: crate::de::from_reader |
29790 |
| partial_eq.rs |
|
2357 |
| ser.rs |
|
27700 |