Strings

A string is a sequence of characters used to represent text in Python. Strings are commonly used for names, messages, addresses, course names, user input, and other text-based information.

What is a String?

A string is text enclosed inside quotes. Python supports both single quotes and double quotes.

name = "Samadhan"
course = 'Python'

print(name)
print(course)

Output

Samadhan
Python

Single and Double Quotes

Python allows strings to be created using either single quotes or double quotes.

name1 = 'Samadhan'
name2 = "Samadhan"

print(name1)
print(name2)

Both variables contain string values.

Multiline Strings

Triple quotes can be used when a string needs to span multiple lines.

message = """Welcome to
CIIT Training Institute.
Learn Python step by step."""

print(message)

Output

Welcome to
CIIT Training Institute.
Learn Python step by step.

String Indexing

Each character in a string has a position called an index. Python string indexing starts from 0.

name = "SAM!"

print(name[0])
print(name[1])
print(name[2])
print(name[3])

Output:

S
A
M
!

Negative Indexing

Python also supports negative indexing. The last character has index -1.

name = "Python"

print(name[-1])
print(name[-2])

Output

n
o

String Slicing

Slicing is used to extract a portion of a string. The syntax is:

string[start:end]

The start index is included, while the end index is excluded.

text = "Python"

print(text[0:3])
print(text[2:6])

Output

Pyt
thon

Finding String Length

The len() function returns the number of characters in a string.

name = "Samadhan"

print(len(name))

Output

8

String Concatenation

Concatenation means joining two or more strings. The + operator can be used to join strings.

first_name = "Samadhan"
last_name = "Patole"

full_name = first_name + " " + last_name

print(full_name)

Output

Samadhan Patil

String Repetition

The * operator can repeat a string multiple times.

message = "Hi "

print(message * 3)

Output

Hi Hi Hi 

Changing String Case

Python provides methods such as upper() and lower() to change the case of a string.

text = "Python Programming"

print(text.upper())
print(text.lower())

Output

PYTHON PROGRAMMING
python programming

Removing Extra Spaces

The strip() method removes leading and trailing whitespace from a string.

name = "   Samadhan   "

print(name.strip())

Output

Samadhan

Replacing Text

The replace() method replaces one piece of text with another.

course = "Learn Java"

new_course = course.replace("Java", "Python")

print(new_course)

Output

Learn Python

Finding Text

The find() method returns the index of the first occurrence of a substring.

text = "Python Programming"

position = text.find("Program")

print(position)

Output:

7

Checking Text using in

The in operator can check whether a particular text exists inside another string.

course = "Python Full Stack"

print("Python" in course)
print("Java" in course)

Output

True
False

Splitting a String

The split() method divides a string into a list based on a separator.

courses = "Python,Java,C#"

result = courses.split(",")

print(result)

Output

['Python', 'Java', 'C#']

Joining Strings

The join() method combines multiple strings into one string.

courses = ["Python", "Java", "C#"]

result = ", ".join(courses)

print(result)

Output

Python, Java, C#

String Formatting using f-Strings

f-strings provide a simple way to insert variables directly into a string.

name = "Samadhan"
course = "Python"

message = f"{name} is learning {course}"

print(message)

Output

Samadhan is learning Python

Strings are Immutable

Python strings are immutable. This means individual characters of an existing string cannot be changed directly.

Instead, a new string is created when a modified value is required.

name = "Python"

name = "Python Programming"

print(name)

Output:

Python Programming

Example 🌍🤓

Let's create a simple student profile using strings at CIIT Training Institute 📩👨‍🏫...!.

student_name = "Pradnya"
course = "Python Full Stack"
institute = "CIIT Training Institute📩👨‍🏫..."

message = (
    f"Student: {student_name}\n"
    f"Course: {course}\n"
    f"Institute: {institute}"
)

print(message)

Output

Student: Pradnya
Course: Python Full Stack
Institute: CIIT Training Institute📩👨‍🏫...

name = "Om"
city = "Pune"
course = "Python"
institute = "CIIT Training Institute 📩👨‍🏫..."

print(
    f"My name is {name}. "
    f"I live in {city}. "
    f"I am learning {course} at {institute}."
)

My name is Om. I live in Pune. I am learning Python at CIIT Training Institute 📩👨‍🏫....