Search (get)

Visual hash buckets with separate chaining collision handling

Add entries first:

Search by key:

Hash Table (Size: 8)

Collisions: 0

0

bucket[0]

empty

1

bucket[1]

empty

2

bucket[2]

empty

3

bucket[3]

empty

4

bucket[4]

empty

5

bucket[5]

empty

6

bucket[6]

empty

7

bucket[7]

empty

Hash Function: sum of char codes % 8. Collision handling: Separate Chaining.

What is HashMap Search?

HashMap Search operation retrieves a value by its key. It uses the hash function to compute the bucket index, then searches the bucket for the matching key and returns its value.

Search Operation Steps

Call get("name")
Compute hash("name") = 3 → go to index 3
Search bucket at index 3 for key "name"
Key found → return its value "Alice"
If key not found → return null/undefined

Time Complexity (Average): O(1)
Time Complexity (Worst): O(n)
Space Complexity: O(1)

Time Complexity Analysis

Edge Cases

Key not found: Returns null/undefined without throwing error
Collision chain: Searches entire chain at bucket until key matches or chain ends

Real-world Applications

Cache lookups
Database record retrieval by primary key
Two Sum problem — checking if complement exists
Frequency counting in strings/arrays
Routing tables in networking

Search is the most frequently used HashMap operation with O(1) average time complexity, making HashMap ideal for fast lookups in real-world applications.

// HashMap Search in JavaScript
const hashMap = new Map();

// Insert some entries
hashMap.set("name", "Alice");
hashMap.set("age", 25);
hashMap.set("city", "New York");

// Search for a key
console.log(hashMap.get("name")); // Alice
console.log(hashMap.get("age"));  // 25

// Check if key exists
console.log(hashMap.has("city")); // true
console.log(hashMap.has("country")); // false

Explore other operations

Insert

Delete

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Search (get)

Hash Table (Size: 8)

What is HashMap Search?

Search Operation Steps

Time Complexity Analysis

Edge Cases

Real-world Applications

Explore other operations

Search (get)

Hash Table (Size: 8)

What is HashMap Search?

Search Operation Steps

Time Complexity Analysis

Edge Cases

Real-world Applications

Explore other operations