rust / beginner
Snippet
HashMap for Key-Value Storage
HashMap stores key-value pairs with O(1) average lookup time. Use .get() to safely retrieve values as Option<&V>. The .entry() API allows inserting only if the key doesn't exist using or_insert().
snippet.rs
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use std::collections::HashMap;fn main() {let mut scores = HashMap::new();scores.insert(String::from("Alice"), 100);scores.insert(String::from("Bob"), 85);println!("Alice's score: {:?}", scores.get("Alice"));scores.entry(String::from("Charlie")).or_insert(90);for (name, score) in &scores {println!("{}: {}", name, score);}}
Breakdown
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use std::collections::HashMap;
HashMap must be imported from std::collections
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scores.insert(String::from("Alice"), 100);
Insert requires owned String keys, not &str literals
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scores.get("Alice")
get() returns Option<&V>, None if key missing
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.entry(String::from("Charlie")).or_insert(90)
entry() returns Entry enum; or_insert sets default if absent