Python String Operations

String manipulation utilities including case conversion, formatting, and text transformations

Python String Operations

Python provides powerful string manipulation capabilities. These utilities cover common text processing tasks from case conversion to URL-friendly slug generation.

Case Conversion

Capitalize First Letter

Capitalize the first letter of a string:

def capitalize(s, lower_rest = False):
  return ''.join([s[:1].upper(), (s[1:].lower() if lower_rest else s[1:])])

capitalize('fooBar') # 'FooBar'
capitalize('fooBar', True) # 'Foobar'

Decapitalize First Letter

Lowercase the first letter:

def decapitalize(s, upper_rest = False):
  return ''.join([s[:1].lower(), (s[1:].upper() if upper_rest else s[1:])])

decapitalize('FooBar') # 'fooBar'
decapitalize('FooBar', True) # 'fOOBAR'

Capitalize Every Word

Capitalize the first letter of each word:

def capitalize_every_word(s):
  return s.title()

capitalize_every_word('hello world!') # 'Hello World!'

Convert to Different Cases

Camel Case

Convert strings to camelCase:

from re import sub

def camel(s):
  s = sub(r"(_|-)+", " ", s).title().replace(" ", "")
  return ''.join([s[0].lower(), s[1:]])

camel('some_database_field_name') # 'someDatabaseFieldName'
camel('Some label that needs to be camelized')
# 'someLabelThatNeedsToBeCamelized'
camel('some-javascript-property') # 'someJavascriptProperty'
camel('some-mixed_string with spaces_underscores-and-hyphens')
# 'someMixedStringWithSpacesUnderscoresAndHyphens'

Kebab Case

Convert strings to kebab-case:

from re import sub

def kebab(s):
  return '-'.join(
    sub(r"(\s|_|-)+"," ",
    sub(r"[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+",
    lambda mo: ' ' + mo.group(0).lower(), s)).split())

kebab('camelCase') # 'camel-case'
kebab('some text') # 'some-text'
kebab('some-mixed_string With spaces_underscores-and-hyphens')
# 'some-mixed-string-with-spaces-underscores-and-hyphens'
kebab('AllThe-small Things') # 'all-the-small-things'

Snake Case

Convert strings to snake_case:

from re import sub

def snake(s):
  return '_'.join(
    sub('([A-Z][a-z]+)', r' \1',
    sub('([A-Z]+)', r' \1',
    s.replace('-', ' '))).split()).lower()

snake('camelCase') # 'camel_case'
snake('some text') # 'some_text'
snake('some-mixed_string With spaces_underscores-and-hyphens')
# 'some_mixed_string_with_spaces_underscores_and_hyphens'
snake('AllThe-small Things') # 'all_the_small_things'

URL-Friendly Slugs

Convert any string to a URL-friendly slug:

from re import sub

def slugify(s):
  s = s.lower().strip()
  s = sub(r'[^\w\s-]', '', s)
  s = sub(r'[\s_-]+', '-', s)
  s = sub(r'^-+|-+$', '', s)
  return s

slugify('Hello World!') # 'hello-world'

Trim Whitespace

Remove Leading and Trailing Whitespace

'  Hello  '.strip()    # 'Hello'

Remove Leading Whitespace

'  Hello  '.lstrip()   # 'Hello  '

Remove Trailing Whitespace

'  Hello  '.rstrip()   # '  Hello'

Practical Use Cases

Generate Database Field Names

label = "User's Full Name"
field_name = snake(label)  # 'user_s_full_name'

Create URL Slugs from Titles

title = "10 Tips for Better Python Code!"
url_slug = slugify(title)  # '10-tips-for-better-python-code'

Format API Keys

api_response = "some-api-field"
python_var = snake(api_response)  # 'some_api_field'

Clean User Input

user_input = "  John Doe  \n"
cleaned = user_input.strip()  # 'John Doe'

Convert Between Naming Conventions

javascript_var = "userName"
python_var = snake(javascript_var)  # 'user_name'

python_var = "user_name"
javascript_var = camel(python_var)  # 'userName'

Next Steps

Lists

Learn about list operations

Math

Explore mathematical utilities