Array Methods

Introduction:

  • Python provides a set of built-in methods that you can use to manipulate lists (arrays). These methods make it easy to add, remove, and modify elements in your arrays.

Common Array Methods:

  1. append()
    • Adds an element at the end of the list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.append("Honda")
print(cars)
      •  Output: ['Ford', 'Volvo', 'BMW', 'Honda'] 
  2. clear()
    • Removes all elements from the list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.clear()
print(cars)
      •  Output: [] 
  3. copy()
    • Returns a copy of the list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
new_cars = cars.copy()
print(new_cars)
      •  Output: ['Ford', 'Volvo', 'BMW'] 
  4. count()
    • Returns the number of elements with the specified value.

    • Example:

      python
      fruits = ["apple", "banana", "cherry", "apple"]
print(fruits.count("apple"))
      •  Output: 2 
  5. extend()
    • Adds the elements of a list (or any iterable) to the end of the current list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
more_cars = ["Honda", "Toyota"]
cars.extend(more_cars)
print(cars)
      •  Output: ['Ford', 'Volvo', 'BMW', 'Honda', 'Toyota']
  6. index()
    • Returns the index of the first element with the specified value.

    • Example:

      python
      fruits = ["apple", "banana", "cherry"]
print(fruits.index("banana"))
      •  Output: 1
  7. insert()
    • Adds an element at the specified position.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.insert(1, "Honda")
print(cars)
      •  Output: ['Ford', 'Honda', 'Volvo', 'BMW'] 
  8. pop()
    • Removes the element at the specified position.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.pop(1)
print(cars)
      •  Output: ['Ford', 'BMW'] 
  9. remove()
    • Removes the first item with the specified value.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.remove("Volvo")
print(cars)
      •  Output: ['Ford', 'BMW']
  10. reverse()
    • Reverses the order of the list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.reverse()
print(cars)
      •  Output: ['BMW', 'Volvo', 'Ford'] 
  11. sort()
    • Sorts the list.

    • Example:

      python
      cars = ["Ford", "Volvo", "BMW"]
cars.sort()
print(cars)
      •  Output: ['BMW', 'Ford', 'Volvo']

Exercises:

  1. Add and Remove Elements:

    • Create a list of numbers and add a new number at the end, then remove the first number.

      python
      numbers = [1, 2, 3, 4]
numbers.append(5)
numbers.remove(1)
print(numbers)
      •  Output: [2, 3, 4, 5]
  2. Copy and Clear List:

    • Copy a list of fruits and then clear the original list.

      python
      fruits = ["apple", "banana", "cherry"]
new_fruits = fruits.copy()
fruits.clear()
print(new_fruits)  
print(fruits)
      •  Output: ['apple', 'banana', 'cherry']
      • Output:  [] 

Summary:

  • In this tutorial, we learned about various built-in methods to manipulate arrays in Python. These methods are essential for managing and processing data stored in arrays. Practice using these methods to get comfortable with array manipulation in Python!