Struct NodeList

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pub struct NodeList<'a>(/* private fields */);

Expand description

A list of nodes resulting from a JSONPath query

Each node within the list is a borrowed reference to the node in the original serde_json::Value that was queried.

Implementations§

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impl<'a> NodeList<'a>

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pub fn at_most_one(&self) -> Result<Option<&'a Value>, AtMostOneError>

Extract at most one node from a NodeList

This is intended for queries that are expected to optionally yield a single node.

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo[0]")?;
let node = path.query(&value).at_most_one().unwrap();
assert_eq!(node, Some(&json!("bar")));
let path = JsonPath::parse("$.foo.*")?;
let error = path.query(&value).at_most_one().unwrap_err();
assert!(matches!(error, AtMostOneError(2)));

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pub fn exactly_one(&self) -> Result<&'a Value, ExactlyOneError>

Extract exactly one node from a NodeList

This is intended for queries that are expected to yield exactly one node.

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo[0]")?;
let node = path.query(&value).exactly_one().unwrap();
assert_eq!(node, "bar");
let path = JsonPath::parse("$.foo.*")?;
let error = path.query(&value).exactly_one().unwrap_err();
assert!(matches!(error, ExactlyOneError::MoreThanOne(2)));

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pub fn all(self) -> Vec<&'a Value>

Extract all nodes yielded by the query

This is intended for queries that are expected to yield zero or more nodes.

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo.*")?;
let nodes = path.query(&value).all();
assert_eq!(nodes, vec!["bar", "baz"]);

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pub fn len(&self) -> usize

Get the length of a NodeList

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pub fn is_empty(&self) -> bool

Check if a NodeList is empty

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pub fn iter(&self) -> Iter<'_, &Value>

Get an iterator over a NodeList

Note that NodeList also implements IntoIterator.

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pub fn first(&self) -> Option<&'a Value>

Returns the first node in the NodeList, or None if it is empty

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo.*")?;
let node = path.query(&value).first();
assert_eq!(node, Some(&json!("bar")));

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pub fn last(&self) -> Option<&'a Value>

Returns the last node in the NodeList, or None if it is empty

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo.*")?;
let node = path.query(&value).last();
assert_eq!(node, Some(&json!("baz")));

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pub fn get(&self, index: usize) -> Option<&'a Value>

Returns the node at the given index in the NodeList, or None if the given index is out of bounds.

§Usage

let value = json!({"foo": ["bar", "biz", "bop"]});
let path = JsonPath::parse("$.foo.*")?;
let nodes = path.query(&value);
assert_eq!(nodes.get(1), Some(&json!("biz")));
assert!(nodes.get(4).is_none());

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pub fn one(self) -> Option<&'a Value>

👎Deprecated since 0.5.1: it is recommended to use at_most_one, exactly_one, first, last, or get instead

Extract at most one node from a NodeList

This is intended for queries that are expected to optionally yield a single node.

§Usage

let value = json!({"foo": ["bar", "baz"]});
let path = JsonPath::parse("$.foo[0]")?;
let node = path.query(&value).one();
assert_eq!(node, Some(&json!("bar")));
let path = JsonPath::parse("$.foo.*")?;
let node = path.query(&value).one();
assert!(node.is_none());