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Programming-Idioms

  • Groovy
  • Go

Idiom #298 Copy a map

Create the map y by cloning the map x.

y is a shallow copy, not a deep copy.

y := make(map[K]V, len(x))
for k, v := range x {
	y[k] = v
}

K is the key type.
V is the value type.
import "maps"
y := maps.Clone(x)

maps.Clone is generic and type-safe at compile time.
var y = Map.of(x);
New implementation...
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programming-idioms.org 
y := make(map[K]V, len(x))
for k, v := range x {
	y[k] = v
}
y := maps.Clone(x)
var y = Map.of(x);
Map<K, V> y = x;
my %y = %x;
y = x.copy()
y = x.dup