Python

▶ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> message = "Meet me tonight."
>>> print(message)
Meet me tonight.
>>>
>>> message2 = 'The clock strikes at midnight.'
>>> print(message2)
The clock strikes at midnight.

>>> movie_quote = """One of my favorite lines from The Godfather is:
... I'm going to make him an offer he can't refuse."
... Do you know who said this?"""
>>>

first = 'John'
last = 'Smith'
message = first + ' [' + last + '] is a coder'
print(message)

first = 'John'
last = 'Smith'

msg = f'{first} [{last}] is a coder'
print(msg)

course = 'Python for Beginners'
print(len(course))

course = 'Python for Beginners'
print(course.upper())
print(course.lower())

course = 'Python for Beginners'
print(course.find('P'))
print(course.find('Beginners'))

course = 'Python for Beginners'
print(course.replace('Beginners', 'Absolute Beginners'))

course = 'Python for Beginners'
print('Python' in course)
print('python' in course)

▶ python
Python 2.7.10 (default, Feb 22 2019, 21:55:15) 
[GCC 4.2.1 Compatible Apple LLVM 10.0.1 (clang-1001.0.37.14)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 28
>>> type(a)
<type 'int'>
>>> a
28
>>> print(a)
28
>>> import sys
>>> sys.maxint
9223372036854775807
>>> b = 2147483648
>>> type(b)
<type 'int'>
>>> c = 9223372036854775808
>>> type(c)
<type 'long'>
>>> d = -sys.maxint - 1
>>> type(d)
<type 'int'>
>>> e = 2.718
>>> type(e)
<type 'float'>
>>> z = 3 + 5.7j
>>> type(z)
<type 'complex'>
>>> z.real
3.0
>>> z.imag
5.7

▶ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> z = 2 - 6.1j
>>> type(z)
<class 'complex'>
>>> z.real
2.0
>>> z.imag
-6.1
>>>

▶ python
Python 2.7.10 (default, Feb 22 2019, 21:55:15) 
[GCC 4.2.1 Compatible Apple LLVM 10.0.1 (clang-1001.0.37.14)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 2 # int
>>> b = 3L # long
>>> c = 6.0  # float
>>> d = 12 + 0j  # complex number
>>> # Addition
... a + b  # int + long
5L
>>> # Subtraction
... c - b  # float - long
3.0
>>> Multiplication
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'Multiplication' is not defined
>>> a * c  # int * float
12.0
>>> # Division
... d / c  # complex / float
(2+0j)

>>> 16 / 5
3
>>> 16 % 5
1
>>> float(16) / 5
3.2
>>> 2 / 0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: integer division or modulo by zero

▶ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 16/5
3.2
>>> 20/5
4.0
>>> 16 % 5
1
>>> 16//5
3
>>> 2/0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ZeroDivisionError: division by zero

▶ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> dir()
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']
>>> dir(__builtins__)
['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning', 'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError', 'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning', 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False', 'FileExistsError', 'FileNotFoundError', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError', 'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'ModuleNotFoundError', 'NameError', 'None', 'NotADirectoryError', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError', 'RecursionError', 'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning', 'StopAsyncIteration', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError', 'TimeoutError', 'True', 'TypeError', 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'ZeroDivisionError', '_', '__build_class__', '__debug__', '__doc__', '__import__', '__loader__', '__name__', '__package__', '__spec__', 'abs', 'all', 'any', 'ascii', 'bin', 'bool', 'breakpoint', 'bytearray', 'bytes', 'callable', 'chr', 'classmethod', 'compile', 'complex', 'copyright', 'credits', 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'exec', 'exit', 'filter', 'float', 'format', 'frozenset', 'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex', 'id', 'input', 'int', 'isinstance', 'issubclass', 'iter', 'len', 'license', 'list', 'locals', 'map', 'max', 'memoryview', 'min', 'next', 'object', 'oct', 'open', 'ord', 'pow', 'print', 'property', 'quit', 'range', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'vars', 'zip']
>>> help(hex)
Help on built-in function hex in module builtins:

hex(number, /)
    Return the hexadecimal representation of an integer.

    >>> hex(12648430)
    '0xc0ffee'
>>> hex(10)
'0xa'
>>> 0xa
10

>>> a = 3
>>> b = 5
>>> a == b
False
>>> a != b
True

>>> type(True)
<class 'bool'>
>>> bool(2)
True
>>> bool(-2.1)
True
>>> bool(0)
False
>>> bool('abc')
True
>>> bool(' ')
True
>>> bool('')
False

>>> import datetime
>>> help(datetime.date)

>>> gvr = datetime.date(1956, 1, 31)
>>> print(gvr)
1956-01-31
>>> print(gvr.year)
1956
>>> print(gvr.month)
1
>>> print(gvr.day)
31

>>> mail = datetime.date(2000, 1, 1)
>>> dt = datetime.timedelta(100)
>>> print(mail + dt)
2000-04-10

>>> # Day-name, Month-name Day-#, Year
...
>>> print(gvr.strftime("%A, %B, %d, %Y"))
Tuesday, January, 31, 1956
>>>
>>> message = "GVR was born on {:%A, %B, %d, %Y}."
>>> print(message.format(gvr))
GVR was born on Tuesday, January, 31, 1956.

>>> dir(datetime)
['MAXYEAR', 'MINYEAR', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'date', 'datetime', 'datetime_CAPI', 'time', 'timedelta', 'timezone', 'tzinfo']
>>>
>>> launch_date = datetime.date(2017, 3, 20)
>>> launch_time = datetime.time(22, 27, 0)
>>> launch_datetime = datetime.datetime(2017, 3, 20, 22, 27, 0)
>>>
>>> print(launch_date)
2017-03-20
>>> print(launch_time)
22:27:00
>>> print(launch_datetime)
2017-03-20 22:27:00

>>> print(launch_time.hour)
22
>>> print(launch_time.minute)
27
>>> print(launch_time.second)
0

>>> now = datetime.datetime.today()
>>> print(now)
2019-09-27 23:18:54.381467
>>> print(now.microsecond)
381467

>>> moon_landing = "7/20/1969"
>>> moon_landing_datetime = datetime.datetime.strptime(moon_landing, "%m/%d/%Y")
>>> print(moon_landing_datetime)
1969-07-20 00:00:00
>>> print(type(moon_landing_datetime))
<class 'datetime.datetime'>
>>>

age = int(input('请输入1到100之间的数字:'))
if age >= 18:
	print('adult')
elif age >= 6:
	print('teenager')
else:
	print('kid')

Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> def cm(feet = 0, inches = 0):
...     '''Concerts a length from feet and inches to centimeters.'''
...     inches_to_cm = inches * 2.54
...     feet_to_cm = feet * 12 * 2.54
...     return inches_to_cm + feet_to_cm
>>> cm(feet = 5)
152.4
>>> cm(inches = 70)
177.8
>>> cm(feet = 5, inches = 8)
172.72

>>> def g(x = 0, y):
...     return x + y
...
  File "<stdin>", line 1
SyntaxError: non-default argument follows default argument

>>> def g(y, x = 0):
...     return x + y
...

>>> g(5)
5
>>> g(7, x = 3)
10

def add_end(L=[]):
    L.append('END')
    return L

def add_end(L=None):
    if L is None:
        L = []
    L.append('END')
    return L

def calc(*numbers):
    sum = 0
    for n in numbers:
        sum = sum + n * n
    return sum

def fact(n):
    if n == 1:
        return 1
    return n * fact(n - 1)

def fact(n):
    return fact_iter(n, 1)

def fact_iter(num, product):
    if num == 1:
        return product
    return fact_iter(num - 1, num * product)

>>> s = set([28, True, 2.718, 'set'])
>>> s.add(123)
>>> s
{True, 2.718, 'set', 123, 28}
>>> s.remove(123)
>>> s
{True, 2.718, 'set', 28}
>>> s.discard(28)
>>> s
{True, 2.718, 'set'}
>>> s.clear()
>>> s
set()
>>> len(s)
0
>>>

>>> # Integers 1 - 10
...
>>> odds = set([1, 3, 5, 7, 9])
>>> evens = set([2, 4, 6, 8, 10])
>>> primes = set([2, 3, 5, 7])
>>> composites = set([4, 6, 8, 9, 10])
>>>
>>> odds.union(evens)
{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
>>> evens.union(odds)
{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
>>> odds
{1, 3, 5, 7, 9}
>>> evens
{2, 4, 6, 8, 10}
>>> odds.intersection(primes)
{3, 5, 7}
>>> primes.intersection(evens)
{2}

>>> s1 = set([1, 2, 3])
>>> s2 = set([2, 3, 4])
>>> s1 & s2
{2, 3}
>>> s1 | s2
{1, 2, 3, 4}

>>> 2 in primes
True
>>> 6 in odds
False
>>> 9 not in evens
True

>>> a = ['c', 'b', 'a']
>>> a.sort()
>>> a
['a', 'b', 'c']

>>> a = 'abc'
>>> a.replace('a', 'A')
'Abc'
>>> a
'abc'

>>> primes = [2, 3, 5, 7, 11, 13]
>>> primes.append(17)
>>> primes.append(19)
>>>
>>> primes
[2, 3, 5, 7, 11, 13, 17, 19]
>>> primes.insert(1, 23)
>>> primes
[2, 23, 3, 5, 7, 11, 13, 17, 19]
>>>
>>> primes.pop()
19
>>> primes
[2, 23, 3, 5, 7, 11, 13, 17]
>>> primes.pop(1)
23
>>> primes
[2, 3, 5, 7, 11, 13, 17]
>>> primes[0] = '0'
>>> primes
['0', 3, 5, 7, 11, 13, 17]
>>>
>>> numbers = [5, 2, 1, 7 ,4]
>>> numbers.remove(5)
>>> print(number)
[2, 1, 7, 4]
>>>
>>> numbers.clear()
>>> print(numbers)
[]
>>>
>>> numbers = [5, 2, 1, 5, 7 ,4]
>>> print(numbers.count(5))
2

>>> primes
[2, 3, 5, 7, 11, 13, 17, 19]
>>> primes[0]
2
>>> primes[1]
3
>>> primes[-1]
19

>>> primes
[2, 3, 5, 7, 11, 13, 17, 19]
>>>
>>> primes[2:5]
[5, 7, 11]

>>> L = ['Apple', 123, True]
>>> s = ['python', 'java', ['asp', 'php'], 'scheme']
>>> len(s)
4
>>>
>>> L = []
>>> len(L)
0

>>> numbers = [1, 2, 3]
>>> letters = ['a', 'b', 'c']
>>> numbers + letters
[1, 2, 3, 'a', 'b', 'c']
>>> letters + numbers
['a', 'b', 'c', 1, 2, 3]

matrix = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

for row in matrix:
    for item in row:
        print(item)

>>> post2 = dict(message = "SS Cotopaxi", languange = "English")
>>> print(post2)
{'message': 'SS Cotopaxi', 'languange': 'English'}
>>>
>>> post2["user_id"] = 209
>>> post2["datetime"] = 123456789
>>>
>>> print(post2)
{'message': 'SS Cotopaxi', 'languange': 'English', 'user_id': 209, 'datetime': 123456789}

>>> print(post2["message"])
SS Cotopaxi

>>> if 'location' in post2:
...     print(post2['location'])
... else:
...     print("The post does not contain a location value.")
...
The post does not contain a location value.

>>> try:
...     print(post2['location'])
... except KeyError:
...     print("The post does not contain a location value.")
...
The post does not contain a location value.

>>> loc = post2.get('location', None)
>>> print(loc)
None

>>> for key in post2.keys():
...     value = post2[key]
...     print(key, "=", value)
...
message = SS Cotopaxi
languange = English
user_id = 209
datetime = 123456789

>>> for key, value in post2.items():
...     print(key, "=", value)
...
message = SS Cotopaxi
languange = English
user_id = 209
datetime = 123456789

>>> d.pop('Bob')
75
>>> d
{'Michael': 95, 'Tracy': 85}

>>> key = [1, 2, 3]
>>> d[key] = 'a list'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'

k = ['张三', '李四', '王五']
s = [1000, 3000, 7000]

# print({x : y for x in k for y in s})

print({k : 3000 for k in ['张三', '李四', '王五']})

# 输出结果： {'张三': 3000, '李四': 3000, '王五': 3000}

>>> import sys
>>>
>>> list_eg = [1,2,3,"a","b","c",True,3.1415]
>>> tuple_eg = (1,2,3,"a","b","c",True,3.1415)
>>>
>>> print("List size = ", sys.getsizeof(list_eg))
List size =  128
>>> print("tuple size = ", sys.getsizeof(tuple_eg))
tuple size =  112

>>> import timeit
>>>
>>> list_test = timeit.timeit(stmt="[1,2,3,4,5]", number=1000000)
>>> tuple_test = timeit.timeit(stmt="(1,2,3,4,5)", number=1000000)
>>>
>>> print("List time:", list_test)
List time: 0.0711129419998997
>>> print("Tuple time:", tuple_test)
Tuple time: 0.015337733000023945

>>> empty_tuple = ()
>>> test1 = ("a",)
>>> test2 = ("a", "b")
>>> test3 = ("a", "b", "c")
>>>
>>> print(empty_tuple)
()
>>> print(test1)
('a',)
>>> print(test2)
('a', 'b')
>>> print(test3)
('a', 'b', 'c')

>>> test1 = 1,
>>> test2 = 1, 2
>>> test3 = 1, 2, 3
>>>
>>> print(test1)
(1,)
>>> print(test2)
(1, 2)
>>> print(test3)
(1, 2, 3)

>>> # (age, country, knows_python)
...
>>> survey = (27, "Vietnam", True)
>>> age = survey[0]
>>> country = survey[1]
>>> knows_python = survey[2]
>>>
>>> print("Age =", age)
Age = 27
>>> print("Country =", country)
Country = Vietnam
>>> print("Konws Python ?", knows_python)
Knows Python ? True

>>> survey2 = (21, "Switzerland", False)
>>>
>>> age, country, konws_python = survey2
>>> print("Age =", age)
Age = 21
>>> print("Country =", country)
Country = Switzerland
>>> print("Konws Python ?", knows_python)
Konws Python ? Flase

>>> import logging
>>>
>>> # Create and configure logger
...
>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log")
>>> logger = logging.getLogger()

>>> # Test the logger
...
>>> logger.info("Our first message.")

>>> print(logger.level)
30

>>> import logging
>>>
>>> # Create and configure logger
...
>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.DEBUG)
>>> logger = logging.getLogger()
>>> # Test the logger
...
>>> logger.info("Our first message.")
>>> print(logger.level)
10

>>> import logging
>>>
>>> # Create and configure logger
...
>>> LOG_FORMAT = "%(levelname)s %(asctime)s - %(message)s"
>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.DEBUG, format = LOG_FORMAT)
>>> logger = logging.getLogger()
>>> # Test the logger
...
>>> logger.info("Our first message.")
>>>
>>> print(logger.level)
10

>>> import logging
>>>
>>> # Create and configure logger
...
>>> LOG_FORMAT = "%(levelname)s %(asctime)s - %(message)s"
>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.DEBUG, format = LOG_FORMAT, filemode = 'w')
>>> logger = logging.getLogger()
>>> # Test the logger
...
>>> logger.info("Our SECOND message.")

>>> import logging
>>>
>>> # Create and configure logger
...
>>> LOG_FORMAT = "%(levelname)s %(asctime)s - %(message)s"
>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.DEBUG, format = LOG_FORMAT, filemode = 'w')
>>> logger = logging.getLogger()
>>> # Test messages
...
>>> logger.debug("This id a harmless debug message.")
>>> logger.info("Just some useful info.")
>>> logger.warning("I'm sorry, but I can't do that, Dave.")
>>> logger.error("Did you just try to divide by zero?")
>>> logger.critical("The entire internet is down!!")

>>> logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.ERROR, format = LOG_FORMAT, filemode = 'w')

import logging
import math

# Create and configure logger

LOG_FORMAT = "%(levelname)s %(asctime)s - %(message)s"
logging.basicConfig(filename = "/Users/zhangqiang/Desktop/Programming/Python/practice/Lumberjack.log", level = logging.DEBUG, format = LOG_FORMAT, filemode = 'w')
logger = logging.getLogger()

def quadratic_formula(a, b, c):
    """Return the solutions to the equation ax^2 + bx + c = 0."""
    logger.info("quadratic_formula({0}, {1}, {2})".format(a, b, c))

    # Compute the discriminant
    logger.debug("# Compute the discriminant")
    disc = b**2 - 4*a*c

    # Compute the two roots
    logger.debug("# Compute the two roots.")
    root1 = (-b + math.sqrt(disc)) / (2*a)
    root2 = (-b - math.sqrt(disc)) / (2*a)

    # Return the roots
    logger.debug("# Return the roots.")
    return (root1, root2)

roots = quadratic_formula(1, 0, -4)
print(roots)

roots = quadratic_formula(1, 0, 1)

>>> def fibonacci(n):
...     if n == 1:
...             return 1
...     elif n == 2:
...             return 1
...     elif n > 2:
...             return fibonacci(n - 1) + fibonacci(n - 2)
... 
>>> for n in range(1, 11):
...     print(n, ":", fibonacci(n))
...
1 : 1
2 : 1
3 : 2
4 : 3
5 : 5
6 : 8
7 : 13
8 : 21
9 : 34
10 : 55

fibonacci_cache = {}

def fibonacci(n):
    # If we have cache the value, then return it
    if n in fibonacci_cache:
        return fibonacci_cache[n]

    # Compute the Nth term
    if n == 1:
        value = 1
    elif n == 2:
        value = 1
    elif n > 2:
        value = fibonacci(n-1) + fibonacci(n-2)

    # Cache the value and return it
    fibonacci_cache[n] = value
    return value

for n in range(1, 101):
    print(n, ":", fibonacci(n))

from functools import lru_cache

@lru_cache(maxsize = 1000)
def fibonacci(n):
    if n == 1:
        return 1
    elif n == 2:
        return 1
    elif n > 2:
        return fibonacci(n-1) + fibonacci(n-2)

for n in range(1, 501):
    print(n, ":", fibonacci(n))

from functools import lru_cache

@lru_cache(maxsize = 1000)
def fibonacci(n):
    # Check that the input is a positive integer
    if type(n) != int:
        raise TypeError("n must be a positive int")
    if n < 1:
        raise ValueError("n must be a positive int") 

    # Compute the Nth term 
    if n == 1:
        return 1
    elif n == 2:
        return 1
    elif n > 2:
        return fibonacci(n-1) + fibonacci(n-2)

for n in range(1, 501):
    print(n, ":", fibonacci(n))

# Display 10 random numbers from interval [0, 1)

import random

for i in range(10):
    print(random.random())

# Generate random numbers from interval [3, 7)

import random

for i in range(10):
    print(random.uniform(3, 7))

import random

for i in range(20):
    print(random.normalvariate(0, 1))

▶ python3 ran.py
0.8333294121536797
0.755624821412367
1.478740726288408
0.07938317039808185
0.291908992130876
-0.22504815004343645
-0.8676884812379501
-0.8029345982713375
-1.043558392568845
-3.6805077274987053
0.21430472612013182
1.046297522716622
1.3217391478625042
-0.15949303555422145
-0.12060525806010007
1.1275886234780748
1.691386051133269
0.7738680349015079
1.3120164616558796
-0.9755020257704168

import random

for i in range(20):
    print(random.randint(1, 6))

import random

outcomes = ['rock', 'paper', 'scissors']

for i in range(20):
    print(random.choice(outcomes))

path = "/Users/zhangqiang/Desktop/Programming/Python/blog_learning/google_stock_data.csv"

file = open(path)
for line in file:
    print(line)

>>> path = "/Users/zhangqiang/Desktop/Programming/Python/blog_learning/google_stock_data.csv"
>>> lines = [line for line in open(path)]
>>> lines[0]
'Date,Open,High,Low,Close,Volume,Adj Close\n'
>>> lines[1]
'8/19/2014,585.002622,587.342658,584.002627,586.862643,978600,586.862643\n'

>>> lines[0].strip()
'Date,Open,High,Low,Close,Volume,Adj Close'
>>> lines[0].strip().split(',')
['Date', 'Open', 'High', 'Low', 'Close', 'Volume', 'Adj Close']

>>> dataset = [lines.strip().split(',') for lines in open(path)]
>>> dataset[0]
['Date', 'Open', 'High', 'Low', 'Close', 'Volume', 'Adj Close']
>>> dataset[1]
['8/19/2014', '585.002622', '587.342658', '584.002627', '586.862643', '978600', '586.862643']

import csv

path = "/Users/zhangqiang/Desktop/Programming/Python/blog_learning/google_stock_data.csv"
file = open(path, newline='')
reader = csv.reader(file)

header = next(reader)   # The first line is the header
data = [row for row in reader]  # Read the remaining data

print(reader)
print(data[0])

squares = []
for i in range(1, 101):
    squares.append(i**2)

print(squares)

squares2 = [i**2 for i in range(1, 101)]
print(squares2)

python3 list_com.py

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 2916, 3025, 3136, 3249, 3364, 3481, 3600, 3721, 3844, 3969, 4096, 4225, 4356, 4489, 4624, 4761, 4900, 5041, 5184, 5329, 5476, 5625, 5776, 5929, 6084, 6241, 6400, 6561, 6724, 6889, 7056, 7225, 7396, 7569, 7744, 7921, 8100, 8281, 8464, 8649, 8836, 9025, 9216, 9409, 9604, 9801, 10000]

# x ** 2 % 5 <====> x^2 (mod5)
remainder5 = [x**2 % 5 for x in range(1, 101)]
print(remainder5)

movies = ["Star Wars", "Gandhi", "Casablanca",
          "Shawshank Redemption", "2001: A Space Odyssey", "Groundhog Day"]

gmovies = []
for title in movies:
    if title.startswith("G"):
        gmovies.append(title)
print(gmovies)

movies = ["Star Wars", "Gandhi", "Casablanca",
          "Shawshank Redemption", "2001: A Space Odyssey", "Groundhog Day"]

gmovies = [title for title in movies if title.startswith("G")]
print(gmovies)

movies = [("Citizen Kane", 1941), ("Spirited Away", 2001), ("Gattaca", 1997), ("The Aviator", 2004), ("Raiders of the Lost Ark", 1981)]

pre2k = [title for (title, year) in movies if year < 2000]

print(pre2k)

>>> v = [2, -3, 1]
>>> 4 * v
[2, -3, 1, 2, -3, 1, 2, -3, 1, 2, -3, 1]
>>>
>>> [2, 4, 6] + [1, 3]
[2, 4, 6, 1, 3]

v = [2, -3, 1]
w = [4*x for x in v]
print(w)

A = [1, 3, 5, 7]
B = [2, 4, 6, 8]

cartesian_product = [(a, b) for a in A for b in B]
print(cartesian_product)

>>> import os # 导入os模块，模块的概念后面讲到
>>> [d for d in os.listdir('.')] # os.listdir可以列出文件和目录
['.emacs.d', '.ssh', '.Trash', 'Adlm', 'Applications', 'Desktop', 'Documents', 'Downloads', 'Library', 'Movies', 'Music', 'Pictures', 'Public', 'VirtualBox VMs', 'Workspace', 'XCode']