Java.util.IdentityHashMap.remove() 是IdentityHashMap類的内置方法，用于從地圖中删除任何特定鍵的映射。它基本上删除了Map中任何特定鍵的值。
句法：
Identity_Hash_Map.remove(Object key)
參數：該方法采用一個參數鍵，其映射将從Map中删除。
傳回值：如果該鍵存在，則該方法傳回先前映射到指定鍵的值，否則該方法傳回NULL。
下面的程式說明了java.util.IdentityHashMap.remove() 方法的工作原理
程式1：傳遞現有密鑰時。
// Java code to illustrate the remove() method
import java.util.*;
public class Identity_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty IdentityHashMap
Map Identity_hash = new
IdentityHashMap();
// Mapping string values to int keys
Identity_hash.put(10, "Geeks");
Identity_hash.put(15, "4");
Identity_hash.put(20, "Geeks");
Identity_hash.put(25, "Welcomes");
Identity_hash.put(30, "You");
// Displaying the IdentityHashMap
System.out.println("Initial Mappings are: " +
Identity_hash);
// Removing the existing key mapping
String returned_value =
(String)Identity_hash.remove(20);
// Verifying the returned value
System.out.println("Returned value is: " +
returned_value);
// Displayin the new map
System.out.println("New map is: " + Identity_hash);
}
}
輸出：
Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}
Returned value is: Geeks
New map is: {30=You, 15=4, 10=Geeks, 25=Welcomes}
程式2：傳遞新密鑰時。
// Java code to illustrate the remove() method
import java.util.*;
public class Identity_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty IdentityHashMap
Map Identity_hash =
new IdentityHashMap();
// Mapping string values to int keys
Identity_hash.put(10, "Geeks");
Identity_hash.put(15, "4");
Identity_hash.put(20, "Geeks");
Identity_hash.put(25, "Welcomes");
Identity_hash.put(30, "You");
// Displaying the IdentityHashMap
System.out.println("Initial Mappings are: " +
Identity_hash);
// Removing the new key mapping
String returned_value =
(String)Identity_hash.remove(50);
// Verifying the returned value
System.out.println("Returned value is: " +
returned_value);
// Displayin the new map
System.out.println("New map is: "+Identity_hash);
}
}
輸出：
Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}
Returned value is: null
New map is: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}