In addition to List.Add(), we will cover more methods that make lists easy to work with. For a complete reference of the available properties and methods, see the link below.
Example List
List<string> movies = new List<string>()
{
"Jurassic Park",
"Toy Story",
"Mortal Kombat",
"Braveheart",
"Big Daddy",
"Armageddon",
"Forrest Gump",
"True Lies",
"The Matrix",
"The Lion King"
};
List.Clear() - Removes all elements from the list.
movies.Clear();
Console.WriteLine(movies.Count); // Outputs 0
List.Contains(item) - Determines whether an element is in the list. Returns true if the element is found; otherwise, false.
movies.Contains("Toy Story"); // returns true
movies.Contains("A Bug's Life"); //returns false
List.IndexOf(item) - Returns the index of the first occurrence of a value in the list. If not found, returns -1.
movies.IndexOf("Toy Story"); // returns 1
movies.IndexOf("A Bug's Life"); //returns -1
List.Insert(index, item) - Inserts an element into the list at the specified index. Elements at or to the right of the index get shifted to the right.
movies.Insert(2, "Toy Story 2");
/* {
"Jurassic Park", "Toy Story", "Toy Story 2", "Mortal Kombat", "Braveheart", "Big Daddy",
"Armageddon", "Forrest Gump", "True Lies", "The Matrix", "The Lion King"
} */
List.Remove(item) - Removes the first occurrence of a specific object from the list. Returns true if the item was sucessfully removed; otherwise, false.
movies.Insert("Jurassic Park");
/* {
"Toy Story", "Mortal Kombat", "Braveheart", "Big Daddy", "Armageddon",
"Forrest Gump", "True Lies", "The Matrix", "The Lion King"
} */
List.RemoveAt(index) - Removes the element at the specified index of the list.
movies.RemoveAt(5);
/* {
"Jurassic Park", "Toy Story", "Mortal Kombat", "Braveheart", "Big Daddy",
"Forrest Gump", "True Lies", "The Matrix", "The Lion King"
} */
List.Reverse() - Reverses the order of the elements in the list.
movies.Reverse();
/* {
"The Lion King", "The Matrix", "True Lies", "Forrest Gump", "Armageddon",
"Big Daddy", "Braveheart", "Mortal Kombat", "Toy Story", "Jurassic Park"
} */
List.Sort() - Sorts the elements in the list.
movies.Sort();
/* {
"Armageddon", "Big Daddy", "Braveheart", "Forrest Gump", "Jurassic Park",
"Mortal Kombat", "The Lion King", "The Matrix", "Toy Story", "True Lies"
} */
This activity only uses a subset of the methods, but know that these methods and many more exist to help you work with lists.
bool managingInventory = true;
List<string> inventory = new List<string>()
{
"axe",
"shovel",
"axe",
"rope",
"tent",
"grill",
"poncho",
"sleeping bag",
"flint",
"sleeping bag"
};
Console.WriteLine("--- Inventory Manager ---");
while (managingInventory)
{
Console.WriteLine("\n-Main Menu-");
Console.WriteLine("1) List inventory");
Console.WriteLine("2) Add new item");
Console.WriteLine("3) Insert new item");
Console.WriteLine("4) Find item");
Console.WriteLine("5) Sort inventory");
Console.WriteLine("6) Remove an item");
Console.WriteLine("7) Delete inventory");
Console.WriteLine("8) Exit");
Console.Write("-> ");
string input = Console.ReadLine();
if (input == "1")
{
Console.WriteLine("-Inventory-");
if (inventory.Count == 0)
{
Console.WriteLine("No inventory.");
}
foreach (string item in inventory)
{
Console.WriteLine("- " + item);
}
}
else if (input == "2")
{
Console.Write("New Item: ");
input = Console.ReadLine();
inventory.Add(input);
Console.WriteLine(input + " added to list.");
}
else if (input == "3")
{
Console.Write("New Item: ");
input = Console.ReadLine();
Console.Write($"Which index? (0-{inventory.Count - 1}): ");
int index = Convert.ToInt32(Console.ReadLine());
inventory.Insert(index, input);
Console.WriteLine(input + " inserted into list.");
}
else if (input == "4")
{
Console.Write("Which item? ");
input = Console.ReadLine();
int index = inventory.IndexOf(input);
if (index >= 0)
{
Console.WriteLine($"{input} located at index {index}");
}
else
{
Console.WriteLine("Item not found.");
}
}
else if (input == "5")
{
Console.WriteLine("Sorting inventory.");
inventory.Sort();
}
else if (input == "6")
{
Console.Write("Which item? ");
input = Console.ReadLine();
bool itemRemoved = inventory.Remove(input);
if (itemRemoved)
{
Console.WriteLine(input + " removed.");
}
else
{
Console.WriteLine(input + " not found, or an error occured.");
}
}
else if (input == "7")
{
Console.Write("Are you sure? (y/n) ");
input = Console.ReadLine();
if (input == "y")
{
inventory.Clear();
}
else
{
Console.WriteLine("Canceled.");
}
}
else if (input == "8")
{
Console.WriteLine("Exiting.");
managingInventory = false;
}
}
--- Inventory Manager ---
-Main Menu-
1) List inventory
2) Add new item
3) Insert new item
4) Find item
5) Sort inventory
6) Remove an item
7) Delete inventory
8) Exit
-> 6
Which item? flint
flint removed.
-Main Menu-
1) List inventory
2) Add new item
3) Insert new item
4) Find item
5) Sort inventory
6) Remove an item
7) Delete inventory
8) Exit
-> 5
Sorting inventory.
-Main Menu-
1) List inventory
2) Add new item
3) Insert new item
4) Find item
5) Sort inventory
6) Remove an item
7) Delete inventory
8) Exit
-> 3
New Item: charcoal
Which index? (0-8): 0
charcoal inserted into list.
-Main Menu-
1) List inventory
2) Add new item
3) Insert new item
4) Find item
5) Sort inventory
6) Remove an item
7) Delete inventory
8) Exit
-> 1
-Inventory-
- charcoal
- axe
- axe
- grill
- poncho
- rope
- shovel
- sleeping bag
- sleeping bag
- tent
-Main Menu-
1) List inventory
2) Add new item
3) Insert new item
4) Find item
5) Sort inventory
6) Remove an item
7) Delete inventory
8) Exit