Python Strings

What Are Strings?

A string is a sequence of characters used to represent text in a Python program.

A string can contain letters, numbers, spaces, punctuation marks, and special characters.

"Hello"
"Python"
"12345"
"Python is powerful!"
"student@example.com"

Even when a string contains only numbers, Python treats it as text if it is enclosed in quotation marks.

age = "25"

print(type(age))

<class 'str'>

Creating Strings

The simplest way to create a string is to place text inside quotation marks.

name = "Ali"
city = "Multan"
message = "Welcome to PyLearn!"

print(name)
print(city)
print(message)

Ali
Multan
Welcome to PyLearn!

Strings can be assigned to variables just like numbers, lists, and other Python objects.

Single & Double Quotes

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

name1 = 'Ali'
name2 = "Sara"

print(name1)
print(name2)

Both approaches create strings.

Choosing the Right Quote

Sometimes one quotation style makes your code easier to read.

message = "It's a beautiful day"

quote = 'He said "Python is easy!"'

Multiline Strings

Python supports multiline strings using triple quotes.

message = """Welcome to PyLearn.

Learn Python.
Build projects.
Become confident."""

print(message)

Welcome to PyLearn.

Learn Python.
Build projects.
Become confident.

Triple single quotes can also be used:

text = '''This is
a multiline
string.'''

Strings as Sequences of Characters

A string is not just a single piece of text. It is a sequence of individual characters.

word = "Python"

# Characters:
# P y t h o n

Each character occupies a position within the string. These positions become especially important when we learn string indexing and slicing.

Finding String Length

Python provides the len() function to determine how many characters are contained in a string.

word = "Python"

print(len(word))

6

Spaces are also characters.

text = "Hello World"

print(len(text))

11

The space between Hello and World counts as one character.

String Concatenation

Concatenation means joining strings together. Python uses the + operator for this.

first_name = "Muhammad"
last_name = "Ali"

full_name = first_name + " " + last_name

print(full_name)

Muhammad Ali

age = 25

# This causes an error:
# print("Age: " + age)

print("Age: " + str(age))

String Repetition

Python allows strings to be repeated using the multiplication operator *.

line = "-" * 20

print(line)

--------------------

Another example:

word = "Hi "

print(word * 3)

Hi Hi Hi 

String Membership

The membership operators in and not in can be used to search for text inside a string.

message = "Python is powerful"

print("Python" in message)
print("Java" in message)
print("Java" not in message)

True
False
True

word = "Python"

print("Python" in word)
print("python" in word)

Escape Characters

Escape characters allow us to include special characters or formatting inside strings.

New Line

print("Hello\nWorld")

Hello
World

Tab

print("Name:\tAli")
print("Age:\t25")

Name:   Ali
Age:    25

Quotes Inside Strings

message = "He said \"Python is fun!\""

print(message)

He said "Python is fun!"

Backslash

path = "C:\\Users\\Student"

print(path)

C:\Users\Student

Raw Strings

A raw string tells Python to treat backslashes mostly as ordinary characters instead of interpreting them as escape sequences.

path = r"C:\Users\Student\Documents"

print(path)

C:\Users\Student\Documents

Raw strings are particularly useful when working with Windows paths and regular expressions.

String Immutability

Python strings are immutable. This means that once a string object is created, its individual characters cannot be changed directly.

word = "Python"

# This is not allowed:
# word[0] = "J"

Instead, create a new string.

word = "Python"

word = "J" + word[1:]

print(word)

Jython

Comparing Strings

Strings can be compared using comparison operators.

a = "apple"
b = "apple"
c = "banana"

print(a == b)
print(a == c)
print(a != c)

True
False
True

Python also supports alphabetical-style comparisons based on Unicode code points.

print("apple" < "banana")

True

Whitespace in Strings

Spaces, tabs, and line breaks are characters too. This matters when processing user input or data.

name = "  Ali  "

print(name)
print(len(name))

The spaces at the beginning and end are part of the string.

Later, you'll learn useful string methods such as strip() to remove unwanted whitespace.

Common String Mistakes

Mistake 1 — Forgetting Quotation Marks

# Incorrect
# name = Ali

# Correct
name = "Ali"

Mistake 2 — Mixing String and Integer Values

age = 25

# Incorrect:
# print("Age: " + age)

print("Age: " + str(age))

Mistake 3 — Expecting Strings to Change in Place

Remember that strings are immutable.

Mistake 4 — Ignoring Case

answer = "YES"

print(answer == "yes")

False

Practice Exercises

print("*" * 30)

Mini Challenge — Student Profile Generator

Build a small program that creates a formatted student profile using strings.

Your program should:

• Store a student's name.
• Store their city.
• Store their favorite subject.
• Calculate the length of their name.
• Display a clean profile.

name = "Ali"
city = "Multan"
subject = "Python"

print("=" * 30)
print("STUDENT PROFILE")
print("=" * 30)

print("Name:", name)
print("City:", city)
print("Favorite Subject:", subject)
print("Name Length:", len(name))

print("=" * 30)

==============================
STUDENT PROFILE
==============================
Name: Ali
City: Multan
Favorite Subject: Python
Name Length: 3
==============================