How to Capitalize First Letter in Python: Simple Guide

In Python, you can capitalize the first letter of a string using the str.capitalize() method. This method returns a new string with the first character in uppercase and the rest in lowercase.

Syntax

The syntax to capitalize the first letter of a string is simple:

• string.capitalize(): Returns a new string with the first character capitalized and the rest lowercase.

python

string.capitalize()

Example

This example shows how to use capitalize() to change the first letter of a string to uppercase.

python

text = "hello world"
capitalized_text = text.capitalize()
print(capitalized_text)

Output

Hello world

Common Pitfalls

One common mistake is expecting capitalize() to only change the first letter and keep the rest of the string unchanged. However, it converts all other letters to lowercase.

Also, capitalize() does not modify the original string because strings are immutable in Python.

python

text = "hELLO wORLD"
# Wrong: expecting only first letter change
capitalized_wrong = text.capitalize()
print(capitalized_wrong)  # Output: Hello world

# Correct: if you want to keep the rest unchanged, use slicing
capitalized_correct = text[0].upper() + text[1:]
print(capitalized_correct)  # Output: HELLO wORLD

Output

Hello world
HELLO wORLD

Quick Reference

Summary tips for capitalizing the first letter in Python:

• Use str.capitalize() to capitalize first letter and lowercase the rest.
• Use slicing with str[0].upper() + str[1:] to capitalize first letter and keep the rest unchanged.
• Remember strings are immutable; methods return new strings.

Key Takeaways

Use str.capitalize() to capitalize the first letter and lowercase the rest of the string.

If you want to keep the rest of the string unchanged, use slicing with str[0].upper() + str[1:].

Strings in Python are immutable; methods like capitalize() return new strings without changing the original.

Be aware that capitalize() changes all letters except the first to lowercase.

Always check for empty strings before using slicing to avoid errors.