String capitalize() Method in Python

The capitalize() method in Python is used to change the first letter of a string to uppercase and make all other letters lowercase. It is especially useful when we want to ensure that text follows title-like capitalization, where only the first letter is capitalized.

Let's start with a simple example to understand the capitalize() functions:

s = "hello WORLD"
res = s.capitalize()
print(res)

Hello world

Explanation: In this example, capitalize() method converts the first character "h" to uppercase and change the rest of characters to lowercase.

Syntax of capitalize() Method

s.capitalize()

Parameters:

• None

Return Value: A new string with the first character capitalized and all others in lowercase.

Note: The original string remains unchanged (strings are immutable in Python).

Examples of capitalize() Method

Example 1: Multiple Words

The capitalize() method only affects the first letter of the string and doesn’t capitalize each word in multi-word strings.

s = "multiple WORDS IN a String"
res = s.capitalize()
print(res)

Multiple words in a string

Explanation:

• Only the first character of the entire string is capitalized.
• All other letters are lowercased.
• capitalize() does not capitalize each word individually (unlike title()).

Example 2: When the First Character is a Number

When the first character of a string is a number, capitalize() method does not alter it because it only affects alphabetical characters. Instead, it will simply convert any following alphabetical characters to lowercase.

s = "123hello WORLD"
res = s.capitalize()
print(res)

123hello world

Explanation:

• Since the first character is a number, it’s left unchanged.
• The rest of the string is still lowercased.
• capitalize() skips non-alphabet characters for capitalization.

Related Article:

• upper() Method
• lower() Method
• String slicing