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Function object.update
Looks up key; if it exists applies the update delegate else evaluates the create delegate and adds it to the associative array
void update(K, V, C, U)
(
ref V[K] aa,
K key,
scope C create,
scope U update
)
if (isCreateOperation!(C, V) && isUpdateOperation!(U, V));
Parameters
Name | Description |
---|---|
aa | The associative array. |
key | The key. |
create | The delegate to apply on create. |
update | The delegate to apply on update. |
Example
auto aa = ["k1": 1];
aa .update("k1", {
return -1; // create (won't be executed
}, (ref int v) {
return v + 1; // update
});
writeln(aa["k1"]); // 2
aa .update("k2", {
return 0; // create
}, (ref int v) {
return -1; // update (won't be executed)
});
writeln(aa["k2"]); // 0
Authors
Walter Bright, Sean Kelly
License
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.