Gointrogo1

Maps and structs

Go's two everyday aggregate types.

A map is a hash table keyed by a comparable type; a struct groups named fields and can carry methods — together they model most of your data.

Map literal and comma-ok lookup

Gointro

0ms

carol's age: 0bob: 25 found: truecarol found: false

Reference · output compiled offline, not runnable in-browser

Reading the absent key "carol" yields 0 (int's zero value) with no panic, while comma-ok returns found: true for "bob" and false for "carol" — that boolean is the only reliable way to tell a stored zero from a missing key.