Cookbooks
Python
Chapter 2. Strings
Capitalizing a string

Python:
Capitalizing a string

How to:

Using Python’s Built-in Method:

Python has a built-in method .capitalize() for strings to accomplish this task easily.

my_string = "hello world"
capitalized_string = my_string.capitalize()
print(capitalized_string)

Output:

Hello world

Here’s my own customized capitalize() I use to build this site. I needed to make sure special words like HTML always stay all caps. This also demonstrates doctests:

def capitalize(string: str) -> str:
    """
    Capitalize a string, i.e. make the first letter uppercase.
    Handle special cases like "HTML".

    >>> capitalize("this is html, csv, xml, and http (no REPL).")
    'This is HTML, CSV, XML, and HTTP (no REPL).'

    >>> capitalize("this is json, VBA, an IDE, and yaml in the CLI.")
    'This is JSON, VBA, an IDE, and YAML in the CLI.'
    """
    return (
        string
            .capitalize()
            .replace('cli',  'CLI')
            .replace('csv',  'CSV')
            .replace('html', 'HTML')
            .replace('http', 'HTTP')
            .replace('ide',  'IDE')
            .replace('json', 'JSON')
            .replace('repl', 'REPL')
            .replace('vba',  'VBA')
            .replace('xml',  'XML')
            .replace('yaml', 'YAML')
    )

Handling Multiple Words:

For scenarios where you want each word in a string to start with a capital letter (such as titles), the .title() method can be applied.

my_title = "python programming essentials"
title_case = my_title.title()
print(title_case)

Output:

Python Programming Essentials

Using Third-Party Libraries:

While Python’s standard library is equipped for basic string capitalization, libraries like textblob can offer more nuanced control, especially for natural language processing.

First, ensure you have textblob installed:

pip install textblob

Then, use it to capitalize strings, keeping in mind that textblob’s capitalize might work differently based on the context of use:

from textblob import TextBlob

my_sentence = "this is a test sentence"
blob = TextBlob(my_sentence)
capitalized_blob = TextBlob(blob.string.capitalize())
print(capitalized_blob)

Output:

This is a test sentence

Remember, while the capitalize() and title() methods are universally useful, leveraging libraries like textblob can provide additional flexibility for specific applications.

Concatenating strings