Go Maps

Go (Golang) – Maps

A map in Go is a built-in reference data type that stores data in key–value pairs.
Maps are commonly used for fast lookups, dictionaries, and configurations.

 Declaring

Using make()

Short Declaration

 Initializing Maps with Values

 Adding & Updating Map Elements

 Accessing Map Elements

⚠ If key does not exist, Go returns zero value.

 Checking if Key Exists (Important)

 Deleting Map Elements

 Looping Through

⚠ Map iteration order is random.

 Map with Different Data Types

 Map of Slices

 Nested

 Reference Types

 Nil Map vs Empty Map

•  Writing to nil map causes panic
•  Reading from nil map is allowed

 Map Keys – Rules

•  Keys must be comparable
• Slices, maps, functions cannot be keys

Valid keys:

Best Practices

•  Always initialize before writing
•  Use comma ok to check existence
•  Avoid relying on order
•  Use It for fast lookups

Summary

• It store key–value pairs

• Reference type

• Fast access

• Unordered collection