feat: ✨ hash_maps

.gitignore

@@ -2,6 +2,7 @@
 # will have compiled files and executables
 /target/
 target/
+.vscode/
 
 # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
 # More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

23-hash_maps/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "hash_maps"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

23-hash_maps/src/main.rs

@@ -0,0 +1,42 @@
+use std::collections::HashMap;
+
+fn main() {
+    println!("Hello, world!");
+
+    // this is how we define hash map
+    let mut hash_map = HashMap::new();
+    // we can add key, value pairs like this
+    hash_map.insert("Ahmet", 0);
+    hash_map.insert("Kaan", 1);
+    hash_map.insert("Gümüş", 2);
+
+    // we can iterate pairs
+    for hash in &hash_map {
+        println!("{:#?}", hash);
+    }
+
+    // we're able to collect all keys with it
+    println!("{:#?}", hash_map.keys());
+
+    // this will return option(value)
+    println!("{:#?}", hash_map.get("Ahmet"));
+
+    // this will return option(key, value) pair
+    println!("{:#?}", hash_map.get_key_value("Ahmet"));
+
+    // inserting same key changes original value if exists
+    hash_map.insert("Ahmet", 10);
+    println!("{:#?}", hash_map.get_key_value("Ahmet"));
+
+    // this allows us to insert a value if it haven't existed
+    // If exists there will be no change
+    println!("{}", hash_map.entry("Ahmet").or_insert(13));
+    println!("{}", hash_map.entry("WhoIsThis").or_insert(13));
+    println!("{}", hash_map.entry("WhoIsThisAgain").or_insert(13));
+
+    // this tries to remove key and returns option(value)
+    println!("{:#?}", hash_map.remove("WhoIsThis"));
+
+    //this also removes but returns not only value but with key, option(key, value)
+    println!("{:#?}", hash_map.remove_entry("WhoIsThisAgain"));
+}