For Loops

Go has one loop word: for.

You use it for counted loops, while-style loops, and forever loops.

You also use it to walk slices, maps, strings, and channels.

Learn for well and you cover almost all repetition in Go.

Classic three-part for

Init runs once at the start.

Condition is checked each round.

Post runs after each round.

Leave out any part you do not need.

While-style loop

Write for condition { ... } for a while-style loop.

It keeps going while the check is true.

Forever loop and break

Write a bare for for a loop that keeps going.

Exit with break when you are ready.

Think of a hamster wheel with an emergency stop button.

continue

continue skips the rest of this round.

Then the loop starts the next round.

Range over a slice

range gives the index and the value.

Use _ to ignore something you do not need.

This is clearer than counting indexes by hand.

Use range when walking collections. It is clearer than counting by hand.