What is Functional Programming?

Functional programming is a programming style that treats computation as evaluating mathematical functions. Instead of changing data (mutating), you create new data. Think of it like math: f(x) = x + 1 doesn't change x, it produces a new value.

Core Principles:

• Pure functions: Same input always gives same output, no side effects
• Immutability: Don't modify data, create new versions
• First-class functions: Functions are values you can pass around
• Higher-order functions: Functions that take or return functions

Benefits:

• Predictable: Easier to reason about and test
• Parallelizable: No shared mutable state
• Composable: Build complex functions from simple ones
• Fewer bugs: Immutability prevents accidental changes

Common Patterns:

• Map: Transform each element
• Filter: Keep elements that match criteria
• Reduce: Combine elements into one value