rustHow to sort a Rust HashMap?

A Rust HashMap can be sorted using the sort_by method. This method takes a closure as an argument which is used to compare two elements of the HashMap. The closure should return Ordering::Less if the first element is less than the second, Ordering::Equal if they are equal, and Ordering::Greater if the first element is greater than the second.

Example code

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

let mut sorted_map = map.into_iter().collect::<Vec<_>>();
sorted_map.sort_by(|a, b| a.1.cmp(&b.1));

Output example

[("a", 1), ("b", 2), ("c", 3)]

Code explanation

1. let mut map = HashMap::new();: This creates a new empty HashMap.
2. map.insert("a", 1);: This inserts a key-value pair into the HashMap.
3. let mut sorted_map = map.into_iter().collect::<Vec<_>>();: This converts the HashMap into a vector of tuples.
4. sorted_map.sort_by(|a, b| a.1.cmp(&b.1));: This sorts the vector of tuples using the sort_by method. The closure passed to the method compares the second element of each tuple (a.1 and b.1) and returns Ordering::Less, Ordering::Equal, or Ordering::Greater depending on the comparison result.

Helpful links

• Rust HashMap documentation
• Rust sort_by method documentation

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