Download our e-book of Introduction To Python

Top Discussion

How can I write Python code to change a date string from "mm/dd/yy hh: mm" format to "YYYY-MM-DD HH: mm" format? Exception Type: JSONDecodeError at /update/ Exception Value: Expecting value: line 1 column 1 (char 0) Someone guide please. How to store the name of IV in a list which show non linear behavior ?.......How to understand data is linear or non linear ? 'collections.OrderedDict' object has no attribute 'status_code' What is the difference between a module and a package in Python? How can i use pyspark to parallelize a file's payload How to leave/exit/deactivate a Python virtualenvironment Join Discussion

Top Courses

Webinars

Generative AI Journey in Data Science

Dec 6th (8:00 PM) 2004 Registered

More webinars

Sequences and Collections in Python

Pallavi Dhotre

2 years ago

Sequences and Collections in Python | insideAIML

Table of Content

Introduction

Sequence data type in Python

Sequence Types in Python

Lists
Tuples
Strings
Byte sequence
Byte array
Range object

Operations on Sequence Types in Python

Concatenation
Replication
Membership
Slice

Functions of Sequence Types in Python

len()
min(), max()

Collections Module in python

Sets

Dictionaries

Summary

Introduction

Previously we have l earned the data structures of python. In this article, we are going to discuss sequence data type in python and collections module in python in depth. But before that, we should know the difference between sequence and collections. Ordered data types in python like lists, tuples strings are called sequences because we can access them sequentially. Unordered data types such as dictionaries and sets are known as collections.

Sequence Data Type in Python

Sequence data type in python is a collection of ordered elements. The order in which we insert the data items into the data structure, in the same order we can access them that’s why it is called sequence in python. Following are some sequence types in python let’s take a deeper look at them.

Sequence Types in Python

There are 6 sequence types in python – lists, tuples, strings, byte array, byte sequence, and range object.

Lists

In python lists, data items are stored in an ordered manner. The sequence in which they get stored we can access them in the same sequence. Python lists are mutable which means we can modify the elements in the list.

Program

# Sequence types in python - lists
demo_list=[4,5,6] #creating list
print(demo_list[0]) #accessing elements
print(demo_list[1])

Output

4

5

Tuples

In python tuples, data items are stored in an ordered manner. The sequence in which they get stored we can access them in the same sequence. Python tuples are immutable which means we cannot modify the elements in the tuple.

Program

# Sequence types in python - tuple
demo_tuple=(4,5,6) #creating tuple
print(demo_tuple[0]) #accessing elements
print(demo_tuple[1])

Output

4

5

Strings

A collection of characters inside the double quotes or single quotes is identified as a string. We can access a single character from the string in the same way as we do in the lists.

Program

# Sequence types in python - string
demo_string="Welcome" #creating string
print("String is ",demo_string)
print(demo_string[0]) #accessing characters of string by their location
print(demo_string[1])

Output

String is  Welcome
W
e

Byte Sequence

To return the immutable sequence of bytes the bytes() function is used.

Program

# Sequence types in python - byte sequence
demo_size= 5
demo =bytes(demo_size) #creating byte sequence
print(demo)
print(bytes([4,3,5,2,1])) #converting iterables into bytes

Output

b'\x00\x00\x00\x00\x00'
b'\x04\x03\x05\x02\x01'

Byte array

Since byte sequences are immutable, the bytearray() function is used for mutable types.

Program

# sequence in python example - a byte array
print(bytearray(4))
print(bytearray([4,3,5,2,1])) #converting iterables into bytes

Output

bytearray(b'\x00\x00\x00\x00')

bytearray(b'\x04\x03\x05\x02\x01')

Range object

The range() function along with the start and stop range is used to return the elements in the given range.

Program

# sequence in python example - range object
for i in range(1,5):
    print(i)

Output

Operations on Sequence Types in Python

Concatenation

We can combine two sequences using the ‘+’ operator

Program

# Sequence types in python - concatenation
a='India'
b=' is best'
print(a+b)

Output

India is best

Replication

We can print the sequence multiple times using the ‘*’ operator.

Program

# Sequence types in python - Replication
a='hello'
b=' John'
print((a*2)+b)

Output

hellohello John

Membership

We can check if a particular substring is a part of the main string or not using the ‘in’ keyword.

Program

# Sequence types in python - membership
demo_string="Welcome to this new blog"
print('this' in demo_string)

Output

True

Slice

We can display specific parts of the sequence using index slicing in python.

Program

# Sequence types in python - slice
demo_string="Welcome to this new blog"
print(demo_string[3:7])

Output

come

Functions of Sequence Types in Python

Following are some functions used with the sequences in python.

len()

This will return a length of the sequence

Program

# Sequence types in python - functions
demo_string="Welcome to this new blog"
print(len(demo_string))

Output

min(), max()

The min() and max() function will return the smallest and largest value respectively.

Program

# Sequence types in python - functions
demo_string="Welcome"
print(min(demo_string))
print(max(demo_string))

Output

W

o

Collections Module in Python

Unordered data structures like sets and dictionaries are called collections in python.

Sets

Sets are the unordered collection of data items. Data items are immutable. We cannot access the data items in the similar order we stored them.

Program

# Collections module in python - sets
demo_set={2,3,4}
print(demo_set)

Output

{2, 3, 4}

Dictionaries

Dictionaries are the unordered collection of data items. Data items are stored in key-value pairs. Data items are mutable in nature. We can access the data items using keys.

Program

# Collections module in python - dictionaries
demo_dict={2:'hello',4:'hi',6:'welcome'}
print(demo_dict)
print(demo_dict[2]) #accessing element having key 2

Output

{2: 'hello', 4: 'hi', 6: 'welcome'}
hello

Summary

In this article, we discussed sequence data type in python and collections module in python and python sequence types. Sequence data type in python is a collection of ordered elements. The order in which we insert the data items into the data structure, in the same order we can access them that’s why it is called sequence in python. There are 6 sequence types in python – lists, tuples, strings, byte array, byte sequence, and range object. Unordered data structures like sets and dictionaries are called collections in python. We hope you enjoyed the article. If you have any related queries, feel free to ask in the comment section below.

Liked what you read? Then don’t break the spree. Visit our blog page to read more awesome articles.

Or if you are into videos, then we have an amazing Youtube channel as well. Visit our insideAIML Youtube Channel to learn all about Artificial Intelligence, Deep Learning, Data Science and Machine Learning.

Keep Learning. Keep Growing.

Related Blog

Top Discussion

Top Courses

Webinars

Generative AI Journey in Data Science

Sequences and Collections in Python

Table of Content

Introduction

Sequence Data Type in Python

Sequence Types in Python

Lists

Tuples

Strings

Byte Sequence

Byte array

Range object

Operations on Sequence Types in Python

Concatenation

Replication

Membership

Slice

Functions of Sequence Types in Python

len()

min(), max()

Collections Module in Python

Sets

Dictionaries

Summary

Submit Review