>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

>>> 2   3 * 6
20

>>> (2   3) * 6
30

>>> 2 ** 8
256

>>> 23 // 7
3

>>> 23 % 7
2

>>> (5 - 1) * ((7   1) / (3 - 1))
16.0

>>> 'Alice' 'Bob'
'AliceBob'

>>> 'Alice' * 5
'AliceAliceAliceAliceAlice'

>>> spam = 'Hello'
>>> spam
'Hello'

>>> _spam = 'Hello'

# This is a comment

# This is a
# multiline comment

a = 1  # initialization

def foo():
    """
    This is a function docstring
    You can also use:
    ''' Function Docstring '''
    """

>>> print('Hello world!')
Hello world!

>>> a = 1
>>> print('Hello world!', a)
Hello world! 1

>>> print('What is your name?')   # ask for their name
>>> myName = input()
>>> print('It is good to meet you, {}'.format(myName))
What is your name?
Al
It is good to meet you, Al

>>> len('hello')
5

>>> a = [1, 2, 3]
>>> if a:
>>>     print("the list is not empty!")

>>> str(29)
'29'

>>> print('I am {} years old.'.format(str(29)))
I am 29 years old.

>>> str(-3.14)
'-3.14'

>>> int(7.7)
7

>>> int(7.7)   1
8

>>> 42 == 42
True

>>> 40 == 42
False

>>> 'hello' == 'hello'
True

>>> 'hello' == 'Hello'
False

>>> 'dog' != 'cat'
True

>>> 42 == 42.0
True

>>> 42 == '42'
False

>>> True == True
True

>>> True != False
True

>>> True is True
True

>>> True is not False
True

>>> if a is True:
>>>    pass
>>> if a is not False:
>>>    pass
>>> if a:
>>>    pass

>>> if a is False:
>>>    pass
>>> if a is not True:
>>>    pass
>>> if not a:
>>>    pass

>>> (4 < 5) and (5 < 6)
True

>>> (4 < 5) and (9 < 6)
False

>>> (1 == 2) or (2 == 2)
True

>>> 2   2 == 4 and not 2   2 == 5 and 2 * 2 == 2   2
True

if name == 'Alice':
    print('Hi, Alice.')

name = 'Bob'
if name == 'Alice':
    print('Hi, Alice.')
else:
    print('Hello, stranger.')

name = 'Bob'
age = 5
if name == 'Alice':
    print('Hi, Alice.')
elif age < 12:
    print('You are not Alice, kiddo.')

name = 'Bob'
age = 30
if name == 'Alice':
    print('Hi, Alice.')
elif age < 12:
    print('You are not Alice, kiddo.')
else:
    print('You are neither Alice nor a little kid.')

spam = 0
while spam < 5:
    print('Hello, world.')
    spam = spam   1

while True:
    print('Please type your name.')
    name = input()
    if name == 'your name':
        break
print('Thank you!')

while True:
    print('Who are you?')
    name = input()
    if name != 'Joe':
        continue
    print('Hello, Joe. What is the password? (It is a fish.)')
    password = input()
    if password == 'swordfish':
        break
print('Access granted.')

>>> print('My name is')
>>> for i in range(5):
>>>     print('Jimmy Five Times ({})'.format(str(i)))
My name is
Jimmy Five Times (0)
Jimmy Five Times (1)
Jimmy Five Times (2)
Jimmy Five Times (3)
Jimmy Five Times (4)

>>> for i in range(0, 10, 2):
>>>    print(i)
0
2
4
6
8

>>> for i in range(5, -1, -1):
>>>     print(i)
5
4
3
2
1
0

>>> for i in [1, 2, 3, 4, 5]:
>>>    if i == 3:
>>>        break
>>> else:
>>>    print("only executed when no item of the list is equal to 3")

import random
for i in range(5):
    print(random.randint(1, 10))

import random, sys, os, math

from random import *

import sys

while True:
    print('Type exit to exit.')
    response = input()
    if response == 'exit':
        sys.exit()
    print('You typed {}.'.format(response))

>>> def hello(name):
>>>     print('Hello {}'.format(name))
>>>
>>> hello('Alice')
>>> hello('Bob')
Hello Alice
Hello Bob

import random
def getAnswer(answerNumber):
    if answerNumber == 1:
        return 'It is certain'
    elif answerNumber == 2:
        return 'It is decidedly so'
    elif answerNumber == 3:
        return 'Yes'
    elif answerNumber == 4:
        return 'Reply hazy try again'
    elif answerNumber == 5:
        return 'Ask again later'
    elif answerNumber == 6:
        return 'Concentrate and ask again'
    elif answerNumber == 7:
        return 'My reply is no'
    elif answerNumber == 8:
        return 'Outlook not so good'
    elif answerNumber == 9:
        return 'Very doubtful'

r = random.randint(1, 9)
fortune = getAnswer(r)
print(fortune)

>>> spam = print('Hello!')
Hello!

>>> spam is None
True

>>> print('Hello', end='')
>>> print('World')
HelloWorld

>>> print('cats', 'dogs', 'mice')
cats dogs mice

>>> print('cats', 'dogs', 'mice', sep=',')
cats,dogs,mice

>>> def spam():
>>>     global eggs
>>>     eggs = 'spam'
>>>
>>> eggs = 'global'
>>> spam()
>>> print(eggs)
spam

>>> def spam(divideBy):
>>>     try:
>>>         return 42 / divideBy
>>>     except ZeroDivisionError as e:
>>>         print('Error: Invalid argument: {}'.format(e))
>>>
>>> print(spam(2))
>>> print(spam(12))
>>> print(spam(0))
>>> print(spam(1))
21.0
3.5
Error: Invalid argument: division by zero
None
42.0

>>> def spam(divideBy):
>>>     try:
>>>         return 42 / divideBy
>>>     except ZeroDivisionError as e:
>>>         print('Error: Invalid argument: {}'.format(e))
>>>     finally:
>>>         print("-- division finished --")
>>> print(spam(2))
-- division finished --
21.0
>>> print(spam(12))
-- division finished --
3.5
>>> print(spam(0))
Error: Invalid Argument division by zero
-- division finished --
None
>>> print(spam(1))
-- division finished --
42.0

>>> spam = ['cat', 'bat', 'rat', 'elephant']

>>> spam
['cat', 'bat', 'rat', 'elephant']

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> spam[0]
'cat'

>>> spam[1]
'bat'

>>> spam[2]
'rat'

>>> spam[3]
'elephant'

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> spam[-1]
'elephant'

>>> spam[-3]
'bat'

>>> 'The {} is afraid of the {}.'.format(spam[-1], spam[-3])
'The elephant is afraid of the bat.'

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> spam[0:4]
['cat', 'bat', 'rat', 'elephant']

>>> spam[1:3]
['bat', 'rat']

>>> spam[0:-1]
['cat', 'bat', 'rat']

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> spam[:2]
['cat', 'bat']

>>> spam[1:]
['bat', 'rat', 'elephant']

>>> spam2 = spam[:]
['cat', 'bat', 'rat', 'elephant']
>>> spam.append('dog')
>>> spam
['cat', 'bat', 'rat', 'elephant', 'dog']
>>> spam2
['cat', 'bat', 'rat', 'elephant']

>>> spam = ['cat', 'dog', 'moose']
>>> len(spam)
3

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> spam[1] = 'aardvark'

>>> spam
['cat', 'aardvark', 'rat', 'elephant']

>>> spam[2] = spam[1]

>>> spam
['cat', 'aardvark', 'aardvark', 'elephant']

>>> spam[-1] = 12345

>>> spam
['cat', 'aardvark', 'aardvark', 12345]

>>> [1, 2, 3]   ['A', 'B', 'C']
[1, 2, 3, 'A', 'B', 'C']

>>> ['X', 'Y', 'Z'] * 3
['X', 'Y', 'Z', 'X', 'Y', 'Z', 'X', 'Y', 'Z']

>>> spam = [1, 2, 3]

>>> spam = spam   ['A', 'B', 'C']

>>> spam
[1, 2, 3, 'A', 'B', 'C']

>>> spam = ['cat', 'bat', 'rat', 'elephant']
>>> del spam[2]
>>> spam
['cat', 'bat', 'elephant']

>>> del spam[2]
>>> spam
['cat', 'bat']

>>> supplies = ['pens', 'staplers', 'flame-throwers', 'binders']
>>> for i, supply in enumerate(supplies):
>>>     print('Index {} in supplies is: {}'.format(str(i), supply))
Index 0 in supplies is: pens
Index 1 in supplies is: staplers
Index 2 in supplies is: flame-throwers
Index 3 in supplies is: binders

>>> name = ['Pete', 'John', 'Elizabeth']
>>> age = [6, 23, 44]
>>> for n, a in zip(name, age):
>>>     print('{} is {} years old'.format(n, a))
Pete is 6 years old
John is 23 years old
Elizabeth is 44 years old

>>> 'howdy' in ['hello', 'hi', 'howdy', 'heyas']
True

>>> spam = ['hello', 'hi', 'howdy', 'heyas']
>>> 'cat' in spam
False

>>> 'howdy' not in spam
False

>>> 'cat' not in spam
True

>>> cat = ['fat', 'orange', 'loud']

>>> size = cat[0]

>>> color = cat[1]

>>> disposition = cat[2]

>>> cat = ['fat', 'orange', 'loud']

>>> size, color, disposition = cat

>>> a, b = 'Alice', 'Bob'
>>> a, b = b, a
>>> print(a)
'Bob'

>>> print(b)
'Alice'

>>> spam = 'Hello'
>>> spam  = ' world!'
>>> spam
'Hello world!'

>>> bacon = ['Zophie']
>>> bacon *= 3
>>> bacon
['Zophie', 'Zophie', 'Zophie']

>>> spam = ['Zophie', 'Pooka', 'Fat-tail', 'Pooka']

>>> spam.index('Pooka')
1

>>> spam = ['cat', 'dog', 'bat']

>>> spam.append('moose')

>>> spam
['cat', 'dog', 'bat', 'moose']

>>> spam = ['cat', 'dog', 'bat']

>>> spam.insert(1, 'chicken')

>>> spam
['cat', 'chicken', 'dog', 'bat']

>>> spam = ['cat', 'bat', 'rat', 'elephant']

>>> spam.remove('bat')

>>> spam
['cat', 'rat', 'elephant']

>>> spam = ['cat', 'bat', 'rat', 'elephant']

>>> spam.pop()
'elephant'

>>> spam
['cat', 'bat', 'rat']

>>> spam.pop(0)
'cat'

>>> spam
['bat', 'rat']

>>> spam = [2, 5, 3.14, 1, -7]
>>> spam.sort()
>>> spam
[-7, 1, 2, 3.14, 5]

>>> spam = ['ants', 'cats', 'dogs', 'badgers', 'elephants']
>>> spam.sort()
>>> spam
['ants', 'badgers', 'cats', 'dogs', 'elephants']

>>> spam.sort(reverse=True)
>>> spam
['elephants', 'dogs', 'cats', 'badgers', 'ants']

>>> spam = ['a', 'z', 'A', 'Z']
>>> spam.sort(key=str.lower)
>>> spam
['a', 'A', 'z', 'Z']

>>> spam = ['ants', 'cats', 'dogs', 'badgers', 'elephants']
>>> sorted(spam)
['ants', 'badgers', 'cats', 'dogs', 'elephants']

>>> eggs = ('hello', 42, 0.5)
>>> eggs[0]
'hello'

>>> eggs[1:3]
(42, 0.5)

>>> len(eggs)
3

>>> tuple(['cat', 'dog', 5])
('cat', 'dog', 5)

>>> list(('cat', 'dog', 5))
['cat', 'dog', 5]

>>> list('hello')
['h', 'e', 'l', 'l', 'o']

myCat = {'size': 'fat', 'color': 'gray', 'disposition': 'loud'}

>>> spam = {'color': 'red', 'age': 42}
>>> for v in spam.values():
>>>     print(v)
red
42

>>> for k in spam.keys():
>>>     print(k)
color
age

>>> for i in spam.items():
>>>     print(i)
('color', 'red')
('age', 42)

>>> spam = {'color': 'red', 'age': 42}
>>>
>>> for k, v in spam.items():
>>>     print('Key: {} Value: {}'.format(k, str(v)))
Key: age Value: 42
Key: color Value: red

>>> spam = {'name': 'Zophie', 'age': 7}

>>> 'name' in spam.keys()
True

>>> 'Zophie' in spam.values()
True

>>> # You can omit the call to keys() when checking for a key
>>> 'color' in spam
False

>>> 'color' not in spam
True

>>> picnic_items = {'apples': 5, 'cups': 2}

>>> 'I am bringing {} cups.'.format(str(picnic_items.get('cups', 0)))
'I am bringing 2 cups.'

>>> 'I am bringing {} eggs.'.format(str(picnic_items.get('eggs', 0)))
'I am bringing 0 eggs.'

spam = {'name': 'Pooka', 'age': 5}

if 'color' not in spam:
    spam['color'] = 'black'

>>> spam = {'name': 'Pooka', 'age': 5}
>>> spam.setdefault('color', 'black')
'black'

>>> spam
{'color': 'black', 'age': 5, 'name': 'Pooka'}

>>> spam.setdefault('color', 'white')
'black'

>>> spam
{'color': 'black', 'age': 5, 'name': 'Pooka'}

>>> import pprint
>>>
>>> message = 'It was a bright cold day in April, and the clocks were striking
>>> thirteen.'
>>> count = {}
>>>
>>> for character in message:
>>>     count.setdefault(character, 0)
>>>     count[character] = count[character]   1
>>>
>>> pprint.pprint(count)
{' ': 13,
 ',': 1,
 '.': 1,
 'A': 1,
 'I': 1,
 'a': 4,
 'b': 1,
 'c': 3,
 'd': 3,
 'e': 5,
 'g': 2,
 'h': 3,
 'i': 6,
 'k': 2,
 'l': 3,
 'n': 4,
 'o': 2,
 'p': 1,
 'r': 5,
 's': 3,
 't': 6,
 'w': 2,
 'y': 1}

# in Python 3.5 :
>>> x = {'a': 1, 'b': 2}
>>> y = {'b': 3, 'c': 4}
>>> z = {**x, **y}
>>> z
{'c': 4, 'a': 1, 'b': 3}

# in Python 2.7
>>> z = dict(x, **y)
>>> z
{'c': 4, 'a': 1, 'b': 3}

>>> s = {1, 2, 3}
>>> s = set([1, 2, 3])

>>> s = {}
>>> type(s)
<class 'dict'>

>>> s = {1, 2, 3, 2, 3, 4}
>>> s
{1, 2, 3, 4}

>>> s = {1, 2, 3}
>>> s[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'set' object does not support indexing
>>>

>>> s = {1, 2, 3}
>>> s.add(4)
>>> s
{1, 2, 3, 4}

>>> s = {1, 2, 3}
>>> s.update([2, 3, 4, 5, 6])
>>> s
{1, 2, 3, 4, 5, 6}  # remember, sets automatically remove duplicates

>>> s = {1, 2, 3}
>>> s.remove(3)
>>> s
{1, 2}
>>> s.remove(3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 3

>>> s = {1, 2, 3}
>>> s.discard(3)
>>> s
{1, 2}
>>> s.discard(3)
>>>

>>> s1 = {1, 2, 3}
>>> s2 = {3, 4, 5}
>>> s1.union(s2)  # or 's1 | s2'
{1, 2, 3, 4, 5}

>>> s1 = {1, 2, 3}
>>> s2 = {2, 3, 4}
>>> s3 = {3, 4, 5}
>>> s1.intersection(s2, s3)  # or 's1 & s2 & s3'
{3}

>>> s1 = {1, 2, 3}
>>> s2 = {2, 3, 4}
>>> s1.difference(s2)  # or 's1 - s2'
{1}
>>> s2.difference(s1) # or 's2 - s1'
{4}

>>> s1 = {1, 2, 3}
>>> s2 = {2, 3, 4}
>>> s1.symmetric_difference(s2)  # or 's1 ^ s2'
{1, 4}

itertools.accumulate(iterable[, func])

>>> data = [1, 2, 3, 4, 5]
>>> result = itertools.accumulate(data, operator.mul)
>>> for each in result:
>>>    print(each)
1
2
6
24
120

operator.mul(1, 2)
2
operator.mul(2, 3)
6
operator.mul(6, 4)
24
operator.mul(24, 5)
120

>>> data = [5, 2, 6, 4, 5, 9, 1]
>>> result = itertools.accumulate(data)
>>> for each in result:
>>>    print(each)
5
7
13
17
22
31
32

5
5   2 = 7
7   6 = 13
13   4 = 17
17   5 = 22
22   9 = 31
31   1 = 32

itertools.combinations(iterable, r)

>>> shapes = ['circle', 'triangle', 'square',]
>>> result = itertools.combinations(shapes, 2)
>>> for each in result:
>>>    print(each)
('circle', 'triangle')
('circle', 'square')
('triangle', 'square')

itertools.combinations_with_replacement(iterable, r)

>>> shapes = ['circle', 'triangle', 'square']
>>> result = itertools.combinations_with_replacement(shapes, 2)
>>> for each in result:
>>>    print(each)
('circle', 'circle')
('circle', 'triangle')
('circle', 'square')
('triangle', 'triangle')
('triangle', 'square')
('square', 'square')

itertools.count(start=0, step=1)

>>> for i in itertools.count(10,3):
>>>    print(i)
>>>    if i > 20:
>>>        break
10
13
16
19
22

itertools.cycle(iterable)

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue', 'violet']
>>> for color in itertools.cycle(colors):
>>>    print(color)
red
orange
yellow
green
blue
violet
red
orange

itertools.chain(*iterables)

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue']
>>> shapes = ['circle', 'triangle', 'square', 'pentagon']
>>> result = itertools.chain(colors, shapes)
>>> for each in result:
>>>    print(each)
red
orange
yellow
green
blue
circle
triangle
square
pentagon

itertools.compress(data, selectors)

>>> shapes = ['circle', 'triangle', 'square', 'pentagon']
>>> selections = [True, False, True, False]
>>> result = itertools.compress(shapes, selections)
>>> for each in result:
>>>    print(each)
circle
square

itertools.dropwhile(predicate, iterable)

>>> data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1]
>>> result = itertools.dropwhile(lambda x: x<5, data)
>>> for each in result:
>>>    print(each)
5
6
7
8
9
10
1

itertools.filterfalse(predicate, iterable)

>>> data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1]
>>> result = itertools.filterfalse(lambda x: x<5, data)
>>> for each in result:
>>>    print(each)
5
6
7
8
9
10

itertools.groupby(iterable, key=None)

>>> robots = [{
    'name': 'blaster',
    'faction': 'autobot'
}, {
    'name': 'galvatron',
    'faction': 'decepticon'
}, {
    'name': 'jazz',
    'faction': 'autobot'
}, {
    'name': 'metroplex',
    'faction': 'autobot'
}, {
    'name': 'megatron',
    'faction': 'decepticon'
}, {
    'name': 'starcream',
    'faction': 'decepticon'
}]
>>> for key, group in itertools.groupby(robots, key=lambda x: x['faction']):
>>>    print(key)
>>>    print(list(group))
autobot
[{'name': 'blaster', 'faction': 'autobot'}]
decepticon
[{'name': 'galvatron', 'faction': 'decepticon'}]
autobot
[{'name': 'jazz', 'faction': 'autobot'}, {'name': 'metroplex', 'faction': 'autobot'}]
decepticon
[{'name': 'megatron', 'faction': 'decepticon'}, {'name': 'starcream', 'faction': 'decepticon'}]

itertools.islice(iterable, start, stop[, step])

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue',]
>>> few_colors = itertools.islice(colors, 2)
>>> for each in few_colors:
>>>    print(each)
red
orange

itertools.permutations(iterable, r=None)

>>> alpha_data = ['a', 'b', 'c']
>>> result = itertools.permutations(alpha_data)
>>> for each in result:
>>>    print(each)
('a', 'b', 'c')
('a', 'c', 'b')
('b', 'a', 'c')
('b', 'c', 'a')
('c', 'a', 'b')
('c', 'b', 'a')

>>> num_data = [1, 2, 3]
>>> alpha_data = ['a', 'b', 'c']
>>> result = itertools.product(num_data, alpha_data)
>>> for each in result:
    print(each)
(1, 'a')
(1, 'b')
(1, 'c')
(2, 'a')
(2, 'b')
(2, 'c')
(3, 'a')
(3, 'b')
(3, 'c')

itertools.repeat(object[, times])

>>> for i in itertools.repeat("spam", 3):
    print(i)
spam
spam
spam

itertools.starmap(function, iterable)

>>> data = [(2, 6), (8, 4), (7, 3)]
>>> result = itertools.starmap(operator.mul, data)
>>> for each in result:
>>>    print(each)
12
32
21

itertools.takewhile(predicate, iterable)

>>> data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1]
>>> result = itertools.takewhile(lambda x: x<5, data)
>>> for each in result:
>>>    print(each)
1
2
3
4

itertools.tee(iterable, n=2)

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue']
>>> alpha_colors, beta_colors = itertools.tee(colors)
>>> for each in alpha_colors:
>>>    print(each)
red
orange
yellow
green
blue

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue']
>>> alpha_colors, beta_colors = itertools.tee(colors)
>>> for each in beta_colors:
>>>    print(each)
red
orange
yellow
green
blue

itertools.zip_longest(*iterables, fillvalue=None)

>>> colors = ['red', 'orange', 'yellow', 'green', 'blue',]
>>> data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10,]
>>> for each in itertools.zip_longest(colors, data, fillvalue=None):
>>>    print(each)
('red', 1)
('orange', 2)
('yellow', 3)
('green', 4)
('blue', 5)
(None, 6)
(None, 7)
(None, 8)
(None, 9)
(None, 10)

>>> a = [1, 3, 5, 7, 9, 11]

>>> [i - 1 for i in a]
[0, 2, 4, 6, 8, 10]

>>> b = {"abc", "def"}
>>> {s.upper() for s in b}
{"ABC", "DEF"}

>>> c = {'name': 'Pooka', 'age': 5}
>>> {v: k for k, v in c.items()}
{'Pooka': 'name', 5: 'age'}

>>> c = {'name': 'Pooka', 'first_name': 'Oooka'}
>>> ["{}:{}".format(k.upper(), v.upper()) for k, v in c.items()]
['NAME:POOKA', 'FIRST_NAME:OOOKA']

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

>>> print(r'That is Carol\'s cat.')
That is Carol\'s cat.

>>> 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

>>> from textwrap import dedent
>>>
>>> def my_function():
>>>     print('''
>>>         Dear Alice,
>>>
>>>         Eve's cat has been arrested for catnapping, cat burglary, and extortion.
>>>
>>>         Sincerely,
>>>         Bob
>>>         ''').strip()

>>> spam = 'Hello world!'

>>> spam[0]
'H'

>>> spam[4]
'o'

>>> spam[-1]
'!'

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

>>> spam[:5]
'Hello'

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

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

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

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

>>> spam = 'Hello world!'
>>> fizz = spam[0:5]
>>> fizz
'Hello'

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

>>> 'Hello' in 'Hello'
True

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

>>> '' in 'spam'
True

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

>>> a = [1, 2, 3, 4]
>>> 5 in a
False

>>> 2 in a
True

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

>>> spam = spam.lower()
>>> spam
'hello world!'

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

>>> spam.isupper()
False

>>> 'HELLO'.isupper()
True

>>> 'abc12345'.islower()
True

>>> '12345'.islower()
False

>>> '12345'.isupper()
False

>>> '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(['cats', 'rats', 'bats'])
'cats, rats, bats'

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

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

>>> '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']

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

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

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

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

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

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

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

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

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

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

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

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

>>> import pyperclip

>>> pyperclip.copy('Hello world!')

>>> pyperclip.paste()
'Hello world!'

>>> name = 'Pete'
>>> 'Hello %s' % name
"Hello Pete"

>>> num = 5
>>> 'I have %x apples' % num
"I have 5 apples"

>>> name = 'John'
>>> age = 20'

>>> "Hello I'm {}, my age is {}".format(name, age)
"Hello I'm John, my age is 20"

>>> "Hello I'm {0}, my age is {1}".format(name, age)
"Hello I'm John, my age is 20"

>>> name = "alice"
>>> logging.debug("User name: %s", name)

>>> logging.debug("User name: {}".format(name))

>>> logging.debug("User name: "   name)

>>> name = 'Elizabeth'
>>> f'Hello {name}!'
'Hello Elizabeth!

>>> a = 5
>>> b = 10
>>> f'Five plus ten is {a   b} and not {2 * (a   b)}.'
'Five plus ten is 15 and not 30.'

>>> from string import Template
>>> name = 'Elizabeth'
>>> t = Template('Hey $name!')
>>> t.substitute(name=name)
'Hey Elizabeth!'

>>> import re

>>> phone_num_regex = re.compile(r'\d\d\d-\d\d\d-\d\d\d\d')

>>> mo = phone_num_regex.search('My number is 415-555-4242.')

>>> print('Phone number found: {}'.format(mo.group()))
Phone number found: 415-555-4242

>>> phone_num_regex = re.compile(r'(\d\d\d)-(\d\d\d-\d\d\d\d)')

>>> mo = phone_num_regex.search('My number is 415-555-4242.')

>>> mo.group(1)
'415'

>>> mo.group(2)
'555-4242'

>>> mo.group(0)
'415-555-4242'

>>> mo.group()
'415-555-4242'

>>> mo.groups()
('415', '555-4242')

>>> area_code, main_number = mo.groups()

>>> print(area_code)
415

>>> print(main_number)
555-4242

>>> hero_regex = re.compile (r'Batman|Tina Fey')

>>> mo1 = hero_regex.search('Batman and Tina Fey.')

>>> mo1.group()
'Batman'

>>> mo2 = hero_regex.search('Tina Fey and Batman.')

>>> mo2.group()
'Tina Fey'

>>> bat_regex = re.compile(r'Bat(man|mobile|copter|bat)')

>>> mo = bat_regex.search('Batmobile lost a wheel')

>>> mo.group()
'Batmobile'

>>> mo.group(1)
'mobile'

>>> bat_regex = re.compile(r'Bat(wo)?man')
>>> mo1 = bat_regex.search('The Adventures of Batman')
>>> mo1.group()
'Batman'

>>> mo2 = bat_regex.search('The Adventures of Batwoman')
>>> mo2.group()
'Batwoman'

>>> bat_regex = re.compile(r'Bat(wo)*man')
>>> mo1 = bat_regex.search('The Adventures of Batman')
>>> mo1.group()
'Batman'

>>> mo2 = bat_regex.search('The Adventures of Batwoman')
>>> mo2.group()
'Batwoman'

>>> mo3 = bat_regex.search('The Adventures of Batwowowowoman')
>>> mo3.group()
'Batwowowowoman'

>>> bat_regex = re.compile(r'Bat(wo) man')
>>> mo1 = bat_regex.search('The Adventures of Batwoman')
>>> mo1.group()
'Batwoman'

>>> mo2 = bat_regex.search('The Adventures of Batwowowowoman')
>>> mo2.group()
'Batwowowowoman'

>>> mo3 = bat_regex.search('The Adventures of Batman')
>>> mo3 is None
True

>>> ha_regex = re.compile(r'(Ha){3}')
>>> mo1 = ha_regex.search('HaHaHa')
>>> mo1.group()
'HaHaHa'

>>> mo2 = ha_regex.search('Ha')
>>> mo2 is None
True

>>> greedy_ha_regex = re.compile(r'(Ha){3,5}')
>>> mo1 = greedy_ha_regex.search('HaHaHaHaHa')
>>> mo1.group()
'HaHaHaHaHa'

>>> nongreedy_ha_regex = re.compile(r'(Ha){3,5}?')
>>> mo2 = nongreedy_ha_regex.search('HaHaHaHaHa')
>>> mo2.group()
'HaHaHa'

>>> phone_num_regex = re.compile(r'\d\d\d-\d\d\d-\d\d\d\d') # has no groups

>>> phone_num_regex.findall('Cell: 415-555-9999 Work: 212-555-0000')
['415-555-9999', '212-555-0000']

>>> vowel_regex = re.compile(r'[aeiouAEIOU]')

>>> vowel_regex.findall('Robocop eats baby food. BABY FOOD.')
['o', 'o', 'o', 'e', 'a', 'a', 'o', 'o', 'A', 'O', 'O']

>>> consonant_regex = re.compile(r'[^aeiouAEIOU]')

>>> consonant_regex.findall('Robocop eats baby food. BABY FOOD.')
['R', 'b', 'c', 'p', ' ', 't', 's', ' ', 'b', 'b', 'y', ' ', 'f', 'd', '.', '
', 'B', 'B', 'Y', ' ', 'F', 'D', '.']

>>> begins_with_hello = re.compile(r'^Hello')

>>> begins_with_hello.search('Hello world!')
<_sre.SRE_Match object; span=(0, 5), match='Hello'>

>>> begins_with_hello.search('He said hello.') is None
True

>>> whole_string_is_num = re.compile(r'^\d $')

>>> whole_string_is_num.search('1234567890')
<_sre.SRE_Match object; span=(0, 10), match='1234567890'>

>>> whole_string_is_num.search('12345xyz67890') is None
True

>>> whole_string_is_num.search('12 34567890') is None
True

>>> at_regex = re.compile(r'.at')

>>> at_regex.findall('The cat in the hat sat on the flat mat.')
['cat', 'hat', 'sat', 'lat', 'mat']

>>> name_regex = re.compile(r'First Name: (.*) Last Name: (.*)')

>>> mo = name_regex.search('First Name: Al Last Name: Sweigart')

>>> mo.group(1)
'Al'

>>> mo.group(2)
'Sweigart'

>>> nongreedy_regex = re.compile(r'<.*?>')
>>> mo = nongreedy_regex.search('<To serve man> for dinner.>')
>>> mo.group()
'<To serve man>'

>>> greedy_regex = re.compile(r'<.*>')
>>> mo = greedy_regex.search('<To serve man> for dinner.>')
>>> mo.group()
'<To serve man> for dinner.>'

>>> no_newline_regex = re.compile('.*')
>>> no_newline_regex.search('Serve the public trust.\nProtect the innocent.\nUphold the law.').group()
'Serve the public trust.'

>>> newline_regex = re.compile('.*', re.DOTALL)
>>> newline_regex.search('Serve the public trust.\nProtect the innocent.\nUphold the law.').group()
'Serve the public trust.\nProtect the innocent.\nUphold the law.'

>>> robocop = re.compile(r'robocop', re.I)

>>> robocop.search('Robocop is part man, part machine, all cop.').group()
'Robocop'

>>> robocop.search('ROBOCOP protects the innocent.').group()
'ROBOCOP'

>>> robocop.search('Al, why does your programming book talk about robocop so much?').group()
'robocop'

>>> names_regex = re.compile(r'Agent \w ')

>>> names_regex.sub('CENSORED', 'Agent Alice gave the secret documents to Agent Bob.')
'CENSORED gave the secret documents to CENSORED.'

>>> agent_names_regex = re.compile(r'Agent (\w)\w*')

>>> agent_names_regex.sub(r'\1****', 'Agent Alice told Agent Carol that Agent Eve knew Agent Bob was a double agent.')
A**** told C**** that E**** knew B**** was a double agent.'

phone_regex = re.compile(r'((\d{3}|\(\d{3}\))?(\s|-|\.)?\d{3}(\s|-|\.)\d{4}(\s*(ext|x|ext.)\s*\d{2,5})?)')

phone_regex = re.compile(r'''(
    (\d{3}|\(\d{3}\))?            # area code
    (\s|-|\.)?                    # separator
    \d{3}                         # first 3 digits
    (\s|-|\.)                     # separator
    \d{4}                         # last 4 digits
    (\s*(ext|x|ext.)\s*\d{2,5})?  # extension
    )''', re.VERBOSE)

>>> import os

>>> os.path.join('usr', 'bin', 'spam')
'usr\\bin\\spam'

>>> from pathlib import Path

>>> print(Path('usr').joinpath('bin').joinpath('spam'))
usr/bin/spam

>>> from pathlib import Path

>>> print(Path('usr') / 'bin' / 'spam')
usr/bin/spam

>>> my_files = ['accounts.txt', 'details.csv', 'invite.docx']

>>> for filename in my_files:
>>>     print(os.path.join('C:\\Users\\asweigart', filename))
C:\Users\asweigart\accounts.txt
C:\Users\asweigart\details.csv
C:\Users\asweigart\invite.docx