Common string operations in Python

The string module in Python’s standard library provides following useful constants, classes and a helper function called capwords()

Constants

ascii_letters	The concatenation of lowercase and uppercase constants.
ascii_lowercase	The lowercase letters 'abcdefghijklmnopqrstuvwxyz'
ascii_uppercase	The uppercase letters 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
digits	The string '0123456789'.
hexdigits	The string '0123456789abcdefABCDEF'.
octdigits	The string '01234567'.
punctuation	String of ASCII characters which are considered punctuation characters.
printable	String of ASCII characters digits, ascii_letters, punctuation, andwhitespace.
whitespace	A string containing all ASCII characters that are consideredwhitespace such as space, tab, linefeed, return, formfeed, andvertical tab.

Output

>>> import string
>>> string.ascii_letters
'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
>>> string.ascii_lowercase
'abcdefghijklmnopqrstuvwxyz'
>>> string.ascii_uppercase
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
>>> string.digits
'0123456789'
>>> string.hexdigits
'0123456789abcdefABCDEF'
>>> string.octdigits
'01234567'
>>> string.printable
'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~ \t\n\r\x0b\x0c'
>>> string.punctuation
'!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'
>>> string.whitespace
' \t\n\r\x0b\x0c'

Capwords() function

This function performs following −

Splits the given string argument into words using str.split().
Capitalizes each word using str.capitalize()
and joins the capitalized words using str.join().

Example

>>> text='All animals are equal. Some are more equal'
>>> string.capwords(text)
'All Animals Are Equal. Some Are More Equal'

Formatter class

Python’s built-in str class has format() method using which string can be formatted. Formatter object behaves similarly. This may be useful to write customized formatter class by subclassing this Formatter class.

>>> from string import Formatter
>>> f=Formatter()
>>> f.format('name:{name}, age:{age}, marks:{marks}', name='Rahul', age=30, marks=50)
'name:Rahul, age:30, marks:50'

Template

This class is used to create a string template. It proves useful for simpler string substitutions.

>>> from string import Template
>>> text='My name is $name. I am $age years old'
>>> t=Template(text)
>>> t.substitute(name='Rahul', age=30)
'My name is Rahul. I am 30 years old'