Struct sql::plan::transform_expr::NO_PARAMS [−][src]
struct NO_PARAMS {
__private_field: (),
}
Expand description
An empty parameter type map.
These transformations are expected to run after parameters are bound, so there is no need to provide any parameter type information.
Fields
__private_field: ()
Methods from Deref<Target = BTreeMap<usize, ScalarType>>
Returns a reference to the value corresponding to the key.
The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);
Returns the key-value pair corresponding to the supplied key.
The supplied key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.get_key_value(&1), Some((&1, &"a")));
assert_eq!(map.get_key_value(&2), None);
🔬 This is a nightly-only experimental API. (map_first_last
)
map_first_last
)Returns the first key-value pair in the map. The key in this pair is the minimum key in the map.
Examples
Basic usage:
#![feature(map_first_last)]
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
assert_eq!(map.first_key_value(), None);
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.first_key_value(), Some((&1, &"b")));
🔬 This is a nightly-only experimental API. (map_first_last
)
map_first_last
)Returns the last key-value pair in the map. The key in this pair is the maximum key in the map.
Examples
Basic usage:
#![feature(map_first_last)]
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "b");
map.insert(2, "a");
assert_eq!(map.last_key_value(), Some((&2, &"a")));
Returns true
if the map contains a value for the specified key.
The key may be any borrowed form of the map’s key type, but the ordering on the borrowed form must match the ordering on the key type.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);
Constructs a double-ended iterator over a sub-range of elements in the map.
The simplest way is to use the range syntax min..max
, thus range(min..max)
will
yield elements from min (inclusive) to max (exclusive).
The range may also be entered as (Bound<T>, Bound<T>)
, so for example
range((Excluded(4), Included(10)))
will yield a left-exclusive, right-inclusive
range from 4 to 10.
Panics
Panics if range start > end
.
Panics if range start == end
and both bounds are Excluded
.
Examples
Basic usage:
use std::collections::BTreeMap;
use std::ops::Bound::Included;
let mut map = BTreeMap::new();
map.insert(3, "a");
map.insert(5, "b");
map.insert(8, "c");
for (&key, &value) in map.range((Included(&4), Included(&8))) {
println!("{}: {}", key, value);
}
assert_eq!(Some((&5, &"b")), map.range(4..).next());
Gets an iterator over the entries of the map, sorted by key.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut map = BTreeMap::new();
map.insert(3, "c");
map.insert(2, "b");
map.insert(1, "a");
for (key, value) in map.iter() {
println!("{}: {}", key, value);
}
let (first_key, first_value) = map.iter().next().unwrap();
assert_eq!((*first_key, *first_value), (1, "a"));
Gets an iterator over the keys of the map, in sorted order.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(2, "b");
a.insert(1, "a");
let keys: Vec<_> = a.keys().cloned().collect();
assert_eq!(keys, [1, 2]);
Gets an iterator over the values of the map, in order by key.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
a.insert(1, "hello");
a.insert(2, "goodbye");
let values: Vec<&str> = a.values().cloned().collect();
assert_eq!(values, ["hello", "goodbye"]);
Returns the number of elements in the map.
Examples
Basic usage:
use std::collections::BTreeMap;
let mut a = BTreeMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);
Trait Implementations
type Target = BTreeMap<usize, ScalarType>
type Target = BTreeMap<usize, ScalarType>
The resulting type after dereferencing.
Dereferences the value.
Auto Trait Implementations
impl RefUnwindSafe for NO_PARAMS
impl UnwindSafe for NO_PARAMS
Blanket Implementations
Mutably borrows from an owned value. Read more
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more