.length
Published Feb 27, 2024
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In Dart, the .length
property is a utility for determining the number of key-value pairs contained within a Map instance. It enables developers to efficiently manage and manipulate data structures by providing a quick and reliable means of accessing the size of a Map.
Syntax
Map-variable.length
Map-variable
: It represents a variable that holds a Map object.
Example 1
In the following example, the .length
property is used to get the key-value pairs of a Map instance that uses similar data types:
void main() {Map<String, String> countries = {'USA': 'United States','IRE': 'Ireland','ITLY': 'Italy'};print(countries.length);}
Here is the output for the above example:
3
Example 2
The .length
property can take different data types for its key-value pairs as well:
void main() {Map<String, int> fruits = {'Apple': 3,'Banana': 2,'Mango': 9};print(fruits.length);}
The output for the above example is as follows:
3
Example 3
The .length
property also takes duplicate keys into account and ensures that they are not counted:
void main() {Map<String, int> fruits = {'Apple': 3,'Banana': 2,'Apple': 1};print(fruits.length);}
The above example will produce the following output:
2
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