El método Java.util.EnumMap.containsKey( key ) se utiliza para verificar si una clave específica mencionada en el parámetro está presente en este mapa o no.
Sintaxis:
boolean containsKey(Object key)
Parámetro: El método acepta una clave de parámetro que se refiere a la clave a verificar.
Valor devuelto: el método devuelve verdadero si la clave está presente en EnumMap; de lo contrario, devuelve falso.
Los siguientes programas ilustran el método containsKey():
Programa 1:
// Java program to demonstrate containsKey() method
import java.util.*;
// An enum of gfg visitors is created
public enum gfg_visitors {
India,
United_States,
China,
Japan,
Canada
};
class Enum_map {
public static void main(String[] args)
{
EnumMap<gfg_visitors, String> mp = new
EnumMap<gfg_visitors, String>(gfg_visitors.class);
// values are associated in mp
mp.put(gfg_visitors.India, "61.4%");
mp.put(gfg_visitors.United_States, "18.4%");
mp.put(gfg_visitors.China, "2.5%");
mp.put(gfg_visitors.Japan, "1.1%");
mp.put(gfg_visitors.Canada, "1.1%");
// Check if map contains gfg visitor from United_States
boolean ans = mp.containsKey(gfg_visitors.United_States);
// Prints the result
System.out.println("gfg_visitors from United States: " + ans);
}
}
Producción:
gfg_visitors from United States: true
Programa 2:
// Java program to demonstrate containsKey() method
import java.util.*;
// An enum of gfg visitors is created
public enum gfg_visitors {
India,
United_States,
China,
Japan,
Canada,
Russia
};
class Enum_map {
public static void main(String[] args)
{
EnumMap<gfg_visitors, String> mp = new
EnumMap<gfg_visitors, String>(gfg_visitors.class);
// values are associated in mp
mp.put(gfg_visitors.India, "61.4%");
mp.put(gfg_visitors.United_States, "18.4%");
mp.put(gfg_visitors.China, "2.5%");
mp.put(gfg_visitors.Japan, "1.1%");
mp.put(gfg_visitors.Canada, "1.1%");
// check if map contains gfg visitor from Russia
boolean ans = mp.containsKey(gfg_visitors.Russia);
// prints the result
System.out.println("gfg_visitors from Russia: " + ans);
}
}
Producción:
gfg_visitors from Russia: false