Strings and String Methods

Strings are one of the most common data types in Python. A string is any text wrapped in quotes. You will use strings when working with names, messages, emails, file paths, and user input.

What Is a String?

Strings can use single quotes or double quotes.

name = "Alex"
city = 'Nairobi'
message = "Welcome to Python"

Accessing Characters

Each character in a string has a position called an index.

word = "Python"
print(word[0])
print(word[1])

Output:

P
y

String Length

Use the len() function to count characters.

text = "Python"
print(len(text))

Output:

6

Useful String Methods

Python provides many built-in string methods that help you clean, search, transform, and format text efficiently.

upper()

Convert text to uppercase.

name = "alex"
print(name.upper())

lower()

Convert text to lowercase.

name = "ALEX"
print(name.lower())

strip()

Remove spaces at the beginning and end.

text = "  hello  "
print(text.strip())

replace()

Replace text with new text.

message = "I like Java"
print(message.replace("Java", "Python"))

title()

Capitalize the first letter of each word.

text = "python for everyone"
print(text.title())

capitalize()

Capitalize only the first letter of the string.

text = "python"
print(text.capitalize())

startswith()

Check whether a string starts with specific text.

email = "admin@example.com"
print(email.startswith("admin"))

endswith()

Check whether a string ends with specific text.

file = "report.pdf"
print(file.endswith(".pdf"))

split()

Split text into a list.

text = "red,blue,green"
print(text.split(","))

join()

Join items into a string.

colors = ["red", "blue", "green"]
print(" - ".join(colors))

find()

Find the position of text.

word = "Python"
print(word.find("t"))

String Concatenation

Combine strings using +.

first = "Hello"
second = "World"
print(first + " " + second)

string.format()

Another way to insert values into strings.

name = "Maya"
age = 20
print("My name is {} and I am {} years old.".format(name, age))

You can also control positions:

print("{1} is learning {0}".format("Python", "Maya"))

f-Strings

A cleaner way to insert variables into text.

name = "Maya"
age = 20
print(f"My name is {name} and I am {age} years old.")

Code Along

name = "sam"
print(name.upper())
print(name.capitalize())
print(len(name))

Mini Challenge

Create a variable with your full name and:

• Print it in uppercase
• Print it in lowercase
• Count the letters
• Replace your first name with another name

Real World Use Case

Web apps use string methods to clean form data, validate emails, format messages, and personalize user experiences.

Quiz

1. What is a string?
2. What function counts characters?
3. What does upper() do?
4. What is the difference between concatenation and f-strings?

Assignment

Create a program that asks for a user’s name and prints a personalized welcome message in three different formats.

Summary

You learned what strings are, how indexing works, how to use common string methods, and how to format text professionally in Python.