Manipulating strings

Escape characters

An escape character is created by typing a backslash \ followed by the character you want to insert.

Escape character Prints as
\' Single quote
\" Double quote
\t Tab
\n Newline (line break)
\\ Backslash
\b Backspace
\ooo Octal value
\r Carriage Return 
>>> print("Hello there!\nHow are you?\nI\'m doing fine.")
# Hello there!
# How are you?
# I'm doing fine.

Raw strings

A raw string entirely ignores all escape characters and prints any backslash that appears in the string.

>>> print(r"Hello there!\nHow are you?\nI\'m doing fine.")
# Hello there!\nHow are you?\nI\'m doing fine.

Raw strings are mostly used for regular expression definition.

Multiline Strings

>>> print(
... """Dear Alice,
...
... Eve's cat has been arrested for catnapping,
... cat burglary, and extortion.
...
... Sincerely,
... Bob"""
... )

# Dear Alice,

# Eve's cat has been arrested for catnapping,
# cat burglary, and extortion.

# Sincerely,
# Bob

Indexing and Slicing strings

H   e   l   l   o       w   o   r   l   d    !
0   1   2   3   4   5   6   7   8   9   10   11

Indexing

>>> spam = 'Hello world!'

>>> spam[0]
# 'H'

>>> spam[4]
# 'o'

>>> spam[-1]
# '!'

Slicing

>>> spam = 'Hello world!'

>>> spam[0:5]
# 'Hello'

>>> spam[:5]
# 'Hello'

>>> spam[6:]
# 'world!'

>>> spam[6:-1]
# 'world'

>>> spam[:-1]
# 'Hello world'

>>> spam[::-1]
# '!dlrow olleH'

>>> fizz = spam[0:5]
>>> fizz
# 'Hello'

The in and not in operators

>>> 'Hello' in 'Hello World'
# True

>>> 'Hello' in 'Hello'
# True

>>> 'HELLO' in 'Hello World'
# False

>>> '' in 'spam'
# True

>>> 'cats' not in 'cats and dogs'
# False

upper(), lower() and title()

Transforms a string to upper, lower and title case:

>>> greet = 'Hello world!'
>>> greet.upper()
# 'HELLO WORLD!'

>>> greet.lower()
# 'hello world!'

>>> greet.title()
# 'Hello World!'

isupper() and islower() methods

Returns True or False after evaluating if a string is in upper or lower case:

>>> spam = 'Hello world!'
>>> spam.islower()
# False

>>> spam.isupper()
# False

>>> 'HELLO'.isupper()
# True

>>> 'abc12345'.islower()
# True

>>> '12345'.islower()
# False

>>> '12345'.isupper()
# False

The isX string methods

Method Description
isalpha() returns True if the string consists only of letters.
isalnum() returns True if the string consists only of letters and numbers.
isdecimal() returns True if the string consists only of numbers.
isspace() returns True if the string consists only of spaces, tabs, and new-lines.
istitle() returns True if the string consists only of words that begin with an uppercase letter followed by only lowercase characters.

startswith() and endswith()

>>> 'Hello world!'.startswith('Hello')
# True

>>> 'Hello world!'.endswith('world!')
# True

>>> 'abc123'.startswith('abcdef')
# False

>>> 'abc123'.endswith('12')
# False

>>> 'Hello world!'.startswith('Hello world!')
# True

>>> 'Hello world!'.endswith('Hello world!')
# True

join() and split()

join()

The join() method takes all the items in an iterable, like a list, dictionary, tuple or set, and joins them into a string. You can also specify a separator.

>>> ''.join(['My', 'name', 'is', 'Simon'])
'MynameisSimon'

>>> ', '.join(['cats', 'rats', 'bats'])
# 'cats, rats, bats'

>>> ' '.join(['My', 'name', 'is', 'Simon'])
# 'My name is Simon'

>>> 'ABC'.join(['My', 'name', 'is', 'Simon'])
# 'MyABCnameABCisABCSimon'

split()

The split() method splits a string into a list. By default, it will use whitespace to separate the items, but you can also set another character of choice:

>>> 'My name is Simon'.split()
# ['My', 'name', 'is', 'Simon']

>>> 'MyABCnameABCisABCSimon'.split('ABC')
# ['My', 'name', 'is', 'Simon']

>>> 'My name is Simon'.split('m')
# ['My na', 'e is Si', 'on']

>>> ' My  name is  Simon'.split()
# ['My', 'name', 'is', 'Simon']

>>> ' My  name is  Simon'.split(' ')
# ['', 'My', '', 'name', 'is', '', 'Simon']

Justifying text with rjust(), ljust() and center()

>>> 'Hello'.rjust(10)
# '     Hello'

>>> 'Hello'.rjust(20)
# '               Hello'

>>> 'Hello World'.rjust(20)
# '         Hello World'

>>> 'Hello'.ljust(10)
# 'Hello     '

>>> 'Hello'.center(20)
# '       Hello       '

An optional second argument to rjust() and ljust() will specify a fill character apart from a space character:

>>> 'Hello'.rjust(20, '*')
# '***************Hello'

>>> 'Hello'.ljust(20, '-')
# 'Hello---------------'

>>> 'Hello'.center(20, '=')
# '=======Hello========'

Removing whitespace with strip(), rstrip(), and lstrip()

>>> spam = '    Hello World     '
>>> spam.strip()
# 'Hello World'

>>> spam.lstrip()
# 'Hello World     '

>>> spam.rstrip()
# '    Hello World'

>>> spam = 'SpamSpamBaconSpamEggsSpamSpam'
>>> spam.strip('ampS')
# 'BaconSpamEggs'

Python abs() built-in function Python aiter() built-in function Python all() built-in function Python any() built-in function Python ascii() built-in function Python bin() built-in function Python bool() built-in function Python breakpoint() built-in function Python bytearray() built-in function Python bytes() built-in function Python callable() built-in function Python chr() built-in function Python classmethod() built-in function Python compile() built-in function Python complex() built-in function Python delattr() built-in function Python dict() built-in function Python dir() built-in function Python divmod() built-in function Python enumerate() built-in function Python eval() built-in function Python exec() built-in function Python filter() built-in function Python float() built-in function Python format() built-in function Python frozenset() built-in function Python getattr() built-in function Python globals() built-in function Python hasattr() built-in function Python hash() built-in function Python help() built-in function Python hex() built-in function Python id() built-in function Python __import__() built-in function Python input() built-in function Python int() built-in function Python isinstance() built-in function Python issubclass() built-in function Python iter() built-in function Python len() built-in function Python list() built-in function Python locals() built-in function Python map() built-in function Python max() built-in function Python memoryview() built-in function Python min() built-in function Python next() built-in function Python object() built-in function Python oct() built-in function Python open() built-in function Python ord() built-in function Python pow() built-in function Python print() built-in function Python property() built-in function Python range() built-in function Python repr() built-in function Python reversed() built-in function Python round() built-in function Python set() built-in function Python setattr() built-in function Python slice() built-in function Python sorted() built-in function Python staticmethod() built-in function Python str() built-in function Python sum() built-in function Python super() built-in function Python tuple() built-in function Python type() built-in function Python vars() built-in function Python zip() built-in function