Python String capitalize() Method

The capitalize() method in Python is used to convert the first character of a string to uppercase and the rest to lowercase.

This method is useful when you want to format strings to look like proper sentences or names.

Syntax

string.capitalize()

Returns:

• A new string with the first character capitalized and the rest in lowercase.

Example 1: Basic Usage

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

Hello world

Example 2: All Caps to Capitalized

text = "PYTHON IS FUN"
print(text.capitalize())

Python is fun

Example 3: Already Capitalized

text = "Python programming"
print(text.capitalize())

Python programming

Example 4: Starting with Non-letter Character

text = "123hello"
print(text.capitalize())

123hello

Note: Only the first letter is affected. If the first character is not a letter, nothing changes.

Use Cases

• Formatting user input (e.g., names, titles)
• Creating proper sentence case for display
• Ensuring consistency in strings for comparisons

Does it Modify the Original String?

No. Strings in Python are immutable. capitalize() returns a new string and does not change the original one.

Common Mistakes

• Assuming it capitalizes every word – it only affects the first character.
• For capitalizing every word, use title() instead.

Interview Tip

capitalize() is often used in string normalization or preprocessing tasks before comparison or display.

Summary

• capitalize() returns a new string with the first character uppercase and the rest lowercase.
• Original string remains unchanged.
• Non-letter first characters are not affected.

Practice Problem

Write a program that takes a sentence as input and prints the capitalized version.

sentence = input("Enter a sentence: ")
print("Capitalized:", sentence.capitalize())