rustHow to count elements in a Rust HashMap?
To count elements in a Rust HashMap, you can use the len()
method. This method returns the number of elements in the HashMap.
Example code
use std::collections::HashMap;
let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
println!("Number of elements in the map: {}", map.len());
Output example
Number of elements in the map: 2
Code explanation
-
use std::collections::HashMap;
: This line imports theHashMap
type from thestd::collections
module. -
let mut map = HashMap::new();
: This line creates a new emptyHashMap
and stores it in themap
variable. -
map.insert("a", 1);
andmap.insert("b", 2);
: These lines insert two key-value pairs into themap
HashMap. -
println!("Number of elements in the map: {}", map.len());
: This line prints the number of elements in themap
HashMap.
Helpful links
Related
- How to create a HashMap of structs in Rust?
- How to use a custom hash function with a Rust HashMap?
- How to clone a Rust HashMap?
- How to build a Rust HashMap from an iterator?
- How to use a Rust HashMap in a struct?
- How to implement PartialEq for a Rust HashMap?
- How to lock a Rust HashMap?
- How to convert the keys of a Rust HashMap to a vector?
- How to convert a Rust HashMap to a JSON string?
- How to convert a Rust HashMap to JSON?
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