Dart Map.unmodifiable()
Syntax & Examples
Syntax of Map.unmodifiable
The syntax of Map.Map.unmodifiable constructor is:
Map.unmodifiable(Map other)
This Map.unmodifiable constructor of Map creates an unmodifiable hash-based map containing the entries of other
.
Parameters
Parameter | Optional/Required | Description |
---|---|---|
other | required | The map whose entries will be included in the new unmodifiable map. |
✐ Examples
1 Create an unmodifiable map from integer-string pairs
In this example,
- We create a map named
map1
containing integer-string pairs. - We then create an unmodifiable map using
Map.unmodifiable()
withmap1
as the argument. - The unmodifiable map contains the same entries as
map1
. - We print the unmodifiable map to standard output.
Dart Program
void main() {
var map1 = {1: 'one', 2: 'two', 3: 'three'};
var unmodifiableMap = Map.unmodifiable(map1);
print('Unmodifiable map: $unmodifiableMap');
}
Output
Unmodifiable map: {1: one, 2: two, 3: three}
2 Create an unmodifiable map from string-integer pairs
In this example,
- We create a map named
map2
containing string-integer pairs. - We then create an unmodifiable map using
Map.unmodifiable()
withmap2
as the argument. - The unmodifiable map contains the same entries as
map2
. - We print the unmodifiable map to standard output.
Dart Program
void main() {
var map2 = {'a': 1, 'b': 2, 'c': 3};
var unmodifiableMap = Map.unmodifiable(map2);
print('Unmodifiable map: $unmodifiableMap');
}
Output
Unmodifiable map: {a: 1, b: 2, c: 3}
3 Create an unmodifiable map from string-string pairs
In this example,
- We create a map named
map3
containing string-string pairs. - We then create an unmodifiable map using
Map.unmodifiable()
withmap3
as the argument. - The unmodifiable map contains the same entries as
map3
. - We print the unmodifiable map to standard output.
Dart Program
void main() {
var map3 = {'x': 'apple', 'y': 'banana', 'z': 'cherry'};
var unmodifiableMap = Map.unmodifiable(map3);
print('Unmodifiable map: $unmodifiableMap');
}
Output
Unmodifiable map: {x: apple, y: banana, z: cherry}
Summary
In this Dart tutorial, we learned about Map.unmodifiable constructor of Map: the syntax and few working examples with output and detailed explanation for each example.