This document discusses Python arrays and their methods. It begins by explaining that arrays are similar to lists but have constrained data types. Various array methods are described such as insert(), append(), remove(), and reverse(). Limitations of arrays include only supporting one-dimensional structures; NumPy must be used for multi-dimensional arrays. Example code is provided to create integer and float arrays and print their values.

1. ADVANCED COMPUTER
PROGRAMMING
Lecture 10
By: Ammarah Khalid (Lecturer CS)
Riphah International University (Faisalabad)

2. Python Arrays
• The array module defines an object type which can
compactly represent an array of basic values: characters,
integers, floating point numbers
• Arrays are sequence types and behave very much like
lists, except that the type of objects stored in them is
constrained
• The type is specified at object creation time by using
a type code, which is a single character

3. Python Arrays (Cont.)

4. Python Arrays (Cont.)
• Syntax:
• Example:
• array('l', [1, 2, 3, 4, 5])
• array('d', [1.0, 2.0, 3.14])

5. Python Arrays (Cont.)
# importing "array" for array creations
import array as arr
# creating an array with integer type
a = arr.array('i', [1, 2, 3])
# printing original array
print ("The new created array is : ", end =" ")
for i in range (0, 3):
print (a[i], end =" ")
print()
# creating an array with float type
b = arr.array('d', [2.5, 3.2, 3.3])
# printing original array
print ("The new created array is : ", end =" ")
for i in range (0, 3):
print (b[i], end =" ")

6. Array Methods
• insert(pos,value) – It used to insert an element to the array at
a specific index or position. It will take pos, and value as its
parameters where pos variables tell the position and value is
the value need to insert into array.
• append(value) – It is used to add value or append a value to
the existing array in the end. It will take the value which we
want to add as an argument.
• remove(value) – It removes the given element from the array.
It will take value to remove as an argument and removes the
element from the array and it won’t display the element.
• extend(arr) – It is used to add an array of values at the end of
the existing array created. It will take an array of values or an
array as its input argument.
• pop() - It is used to remove an element from the array. It can
take the argument as a position of the element we want to
remove or by default it removes the element at the last index.

7. Array Methods (Cont.)
• index(value) - It will return the first position of the value in
the array, it will take the value as an argument to it and
returns the first occurrence position of the value in the
array as output.
• reverse() - Reverses the array and returns the reversed
array as an output of it. It doesn’t take any argument.
• fromlist(list) – It is used to add a list to the end of the
array. It will take a list as its input argument and the output
of this function is an array with list appended at the end of
the array.
• count(value) - Tells the total number of occurrences of
the given value in the array. It will take a value as an
argument to it to know the total number of occurrences.

8. Arrays – Limitations
• array module supports only 1D arrays
• In order to work with multi-dimensional arrays, use numpy