In Dart, the **`containsValue`** method is used to check if the map contains a specific value.
# 
#  Syntax 

```dart
bool containsValue(Object? value)
```

# 
#  Parameters 
This method takes the argument, `value`, which represents the value that we want to check for.

##
## Return value 

This method returns `true` if the passed value is equal to any of the values in the map.
We use the == operator for that.

##
## Example 

The code below demonstrates how to check if the `HashMap` contains an entry with a specific value:


import 'dart:collection';
void main() {
  //create a new hashmap which can have string type as key, and int type as value
  HashMap map = new HashMap<String, int>();

  // add two entries to the map
  map["one"] =  1;
  map["two"] =  2;

  print('The map is $map');
  // check if the map has a value 1
  print('map.containsValue(1) is ${map.containsValue(1)}');
  // check if the map has a value 3
  print('map.containsValue(2) is ${map.containsValue(3)}');
}

# 
## Explanation 



* **Line 1**: We import the `collection` library. 

* **Line 4**: We create a new `HashMap` object with the name `map`. 

* **Lines 7 and 8**: We add two new entries to the `map`.

* **Line 12**: We used the `containsValue` method with `1` as an argument. This checks if the map has an entry with the value `1`. In our code, there is an entry with the value `1`. Hence, `true` is returned.

* **Line 13**: We use the `containsValue` method with `3` as an argument. This checks if the map has an entry with the value `3`. In our code, there is no entry with value `3` in the map so `false` is returned.

How to check the map for a specific value in Dart

Use Dart's containsValue method to check if a map contains a specific value, returning true or false.