How to use the containsValue() method of SplayTreeMap in Dart
Overview
The containsValue() method checks if an entry for the specified value is present in the SplayTreeMap.
Syntax
bool containsValue(Object? value)
Parameters
This method takes the argument, value, which represents the value we want to check.
Return value
This method returns a Boolean value as a result. If the passed argument matches any of the values present in the SplayTreeMap object then true is returned. Otherwise, false will be returned.
Code
In the example below we use the containsValue method to check if a specific value is present in the SplayTreeMap:
import 'dart:collection';void main() {//create a new SplayTreeMap which can have int key and string valuesSplayTreeMap map = new SplayTreeMap<int, String>((keya,keyb) => keyb.compareTo(keya));// add five entries to the mapmap[5] = "Five";map[4] = "Four";map[2] = "Two";map[1] = "One";map[3] = "Three";print('The map is $map');// check if the map has a value Oneprint('map.containsValue("One") is ${map.containsValue("One")}');// check if the map has a value Tenprint('map.containsValue("Ten") is ${map.containsValue("Ten")}');}
Explanation
Line 1: We import the collection library.
Line 4: We create a new SplayTreeMap object named map. We pass a compare function as an argument. This function maintains the map entries’. In our case, the compare function orders the elements in descending order.
Lines 7–11: We add five new entries to the map. Now, the map is {5=Five,4=Four,3=Three,2=Two,1=One}.
Line 16: Calls the containsValue method. For this method, we pass One as an argument This will checks if the map object has an entry with One as a value. In our map object, there is one entry with the value One. So, true is returned.
Line 16: Calls the containsValue method. For this method, we pass Ten as an argument This will checks if the map object has an entry with Ten as a value. In our map object, there is no entry present for the value Ten. So, false is returned.
