Go map iteration order is random because the language specification explicitly requires it to prevent code from relying on a specific order. The runtime shuffles the internal hash table layout on every run to ensure this non-determinism.
Why Map Iteration Order Is Random in Go
Go map iteration order is random because the language specification explicitly requires it to prevent code from relying on a specific order. The runtime shuffles the internal hash table layout on every run to ensure this non-determinism.
package main
import "fmt"
func main() {
m := map[string]int{"a": 1, "b": 2, "c": 3}
for k, v := range m {
fmt.Println(k, v) // Order varies every execution
}
}
If you need a specific order, copy the keys into a slice and sort them before iterating.
Go maps are like a bag of items where you can grab them out in any order, not a list where they stay in a fixed line. The language forces this randomness to stop programmers from accidentally writing code that breaks when the internal storage changes. If you need items in a specific sequence, you must sort them yourself after pulling them out of the map.