use std::collections::{HashMap, HashSet};
use std::hash::Hash;
use std::sync::{Arc, Mutex};
pub fn trans_map<K, V, T>(m: &HashMap<K, V>, vf: fn(v: &V) -> T) -> HashMap<K, T>
where
K: Eq + Hash + Clone,
{
let mut ret: HashMap<K, T> = HashMap::new();
for (k, v) in m {
ret.insert(k.clone(), vf(v));
}
ret
}
pub fn group_by_value<K, V>(m: &HashMap<K, V>) -> HashMap<V, Vec<K>>
where
V: Eq + Hash + Clone,
K: Clone,
{
let mut ret: HashMap<V, Vec<K>> = HashMap::new();
for (k, v) in m {
if ret.contains_key(v) {
let keys = ret.get_mut(v).unwrap();
keys.push(k.clone());
} else {
ret.insert(v.clone(), vec![k.clone()]);
}
}
ret
}
pub fn group_by_value_set<K, V>(m: &HashMap<K, V>) -> HashMap<V, HashSet<K>>
where
K: Eq + Hash + Clone,
V: Eq + Hash + Clone,
{
let mut ret: HashMap<V, HashSet<K>> = HashMap::new();
for (k, v) in m {
if ret.contains_key(v) {
let keys = ret.get_mut(v).unwrap();
keys.insert(k.clone());
} else {
let mut set = HashSet::new();
set.insert(k.clone());
ret.insert(v.clone(), set);
}
}
ret
}
pub fn group_by_key<K, V, T>(m: &HashMap<K, V>, kf: fn(k: &K) -> T) -> HashMap<T, HashMap<K, V>>
where
T: Eq + Hash + Clone,
K: Eq + Hash + Clone,
V: Clone,
{
let mut ret: HashMap<T, HashMap<K, V>> = HashMap::new();
for (k, v) in m {
let t = kf(k);
if ret.contains_key(&t) {
let keys = ret.get_mut(&t).unwrap();
keys.insert(k.clone(), v.clone());
} else {
let mut rv = HashMap::new();
rv.insert(k.clone(), v.clone());
ret.insert(t, rv);
}
}
ret
}
pub fn arc_map<K, V>() -> Arc<Mutex<HashMap<K, V>>> {
Arc::new(Mutex::new(HashMap::new()))
}
#[test]
fn test_map() {
let mut m = HashMap::new();
m.insert("1", "2");
m.insert("2", "2");
m.insert("3", "2");
m.insert("11", "1");
m.insert("12", "1");
m.insert("13", "1");
let v = group_by_value_set(&m);
println!("{v:#?}");
}