Storage and Use of Arrays 1

What are arrays?

• a fundamental data structure, and an important part of most programming languages.

• In Python, they are containers that can store more than one item at the same time.

• an ordered collection of elements with every value being of the same data type.

• they can only hold a sequence of multiple items that are of the same type

three ways to import array module

• array.array()

• arr.array()

• array()

• for printing arrays: for i in range ()

import array
import array as arr
from array import

for i in range ()

defining arrays in python

variable_name = array(typecode,[elements])

• List of type code to define Arrays in Python

typecodes

create arrays with a float typecode

import array as arr
b = arr.array('d', [2.5, 3.2, 3.3])
print(b)

If you want to print original copy

for i in range (0, 3):
    print(b[i])

2.5
3.2
3.3

creating an array with integer type

import array as arr
a = arr.array('i', [1,2,4])
print(a)

array('i', [1, 2, 4])

adding elements to an array

• insert(position, value)

• append()

insert(position, element)

a.insert(1,4)
print(a)

array('i', [1, 4, 2, 3])

append(element)

import array

s1 = array.array('i', [1,2,3])
s2 = array.array('i', [4,5,6])
print(s1)
print(s2)
s3 = s1 + s2
print(s3)
s1.append(4)
print(s1)

array('i', [1, 2, 3])
array('i', [4, 5, 6])
array('i', [1, 2, 3, 4, 5, 6])
array('i', [1, 2, 3, 4])

Accessing the elements from an Array

• can access the elements of an array using the index operator [ ]

import array as arr

a = arr.array('i', [1, 2, 3, 4, 5, 6])
print("Access element is: ", a[0])      
print("Access element is: ", a[3])    
b = arr.array('d', [2.5, 3.2, 3.3])
print("Access element is: ", b[1])
print("Access element is: ", b[2])

Access element is:  1
Access element is:  4
Access element is:  3.2
Access element is:  3.3

Remove the elements from an Array

import array
x = array.array('i', [1,2,3,1,5])
print("The new created array is : ")
for i in range (0,5):
    print(x[i])

The new created array is : 
1
2
3
1
5

Remove the elements from an Array using pop(position) function

print("The popped element is : ")
print(x.pop(2))

print("The array after popping is : ")
for i in range (0,4):
    print(x[i])

The popped element is : 
3
The array after popping is : 
1
2
1
5

Remove the elements from an Array using remove(position) function

x.remove(1)
print("The array after removing is : ", end ="")
for i in range (0,3):
    print (x[i])

The array after removing is : 2
1
5