Arrays in Python

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Arrays in Python

In Python, an array is a data structure that stores multiple values of the same data type in a single variable.

Arrays are stored in contiguous memory locations, which makes them efficient for numerical operations.
Python provides arrays using the array module (they are different from lists).

Importing array

Before using arrays, you must import them from the array module:

from array import array

Creating an Array

Each array needs:

A type code (for example: 'i' for integer, 'f' for float)
A list of values of that type

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
print(numbers)

▶ Output will appear here.

Accessing Array Elements

Array elements are accessed using indexing, just like lists (starting from index 0).

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
print(numbers[0]) # 10 (first element)
print(numbers[2]) # 30 (third element)

▶ Output will appear here.

Slicing Arrays

You can extract a part of an array using slicing:

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
print(numbers[1:4]) # array('i', [20, 30, 40])

▶ Output will appear here.

This returns elements from index 1 to 3 (end index is excluded).

Looping Through Arrays

You can iterate over array elements in two common ways:

Using a for loop(direct items)

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
for num in numbers:
 print(num)

▶ Output will appear here.

Using indexing

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
for i in range(len(numbers)):
 print(numbers[i])

▶ Output will appear here.

Array Operations

Append an element at the end

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
numbers.append(60)
print(numbers)

▶ Output will appear here.

Insert at a specific index

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
numbers.insert(2, 25) # Insert 25 at index 2
print(numbers)

▶ Output will appear here.

Remove an element by value

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
numbers.remove(25) # Remove first occurrence of 25
print(numbers)

▶ Output will appear here.

Extend array(add multiple elements)

from array import array
numbers = array('i', [10, 20, 30, 40, 50])
extra = array('i', [70, 80])
numbers.extend(extra)
print(numbers)

▶ Output will appear here.

Array Concatenation

You can combine two arrays of the same type using +:

from array import array
a1 = array('i', [1, 2, 3])
a2 = array('i', [4, 5, 6])
a3 = a1 + a2
print(a3) # array('i', [1, 2, 3, 4, 5, 6])

▶ Output will appear here.

Searching Elements

Use .index(value) to find the index of an element:

from array import array
nums = array('i', [10, 20, 30, 40])
print(nums.index(30)) # 2

▶ Output will appear here.

Array Methods

Method	Description	Example
append(x)	Add item at end	arr.append(10)
insert(i, x)	Insert item at index i
remove(x)	Remove first occurrence of x	arr.remove(3)
pop(i)	Remove item at index i	arr.pop(2)
extend(a2)	Add all elements from another array	arr.extend(a2)
index(x)		arr.index(10)
reverse()	Reverse the array	arr.reverse()
buffer_info()	Return memory address & length	arr.buffer_info()
count(x)	Count occurrences of x	arr.count(2)

Note

Python does not have a true built-in array type like C/Java; instead, we use the array module when all items are of one data type.
For numerical computing, most developers prefer NumPy arrays, which are faster and more powerful.

Example using NumPy:

import numpy as np
arr = np.array([1, 2, 3])
print(arr)

▶ Output will appear here.

Arrays in Python

Arrays in Python

Importing array

Creating an Array

Accessing Array Elements

Looping Through Arrays

Array Operations

Array Concatenation

Array Methods

Note

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