Python Development - Level1

#int
num1 = 1
print(type(num1))

#float
num2 = 2.1
print(type(num2))

#str
a = 'hello world'
print(type(a))

#bool : True/False
b = True
print(type(b))

#list
c = [10, 20, 30]
print(type(c))

#tuple
d = (10, 20, 30)
print(type(d))

#set
e = {10, 20, 30}
print(type(e))

#dict -- key and value
f = {'name': 'TOM', 'age': 18}
print(type(f))

age = 18 
name = 'TOM'
weight = 75.5
student_id = 1

# My ID is 0001
print('My ID is %4d' %(student_id))

# My name is Tom and will be 19 next year
print('My name is %s and will be %d next year' %(name, age + 1))

# 强大的%s: My name is Tom and will be 19 next year
print('My name is %s and will be %s next year' %(name, age + 1))

# 高效的f{}: My name is Tom and will be 19 next year
print(f'My name is {name} and will be {age + 1} next year')

# print a value in percentage
value = 0.20009
# precp_MWF:20.0%
print("precp_MWF" + ":" + " %.1f%%" %(value*100))

print('Hellow world', end="\n")
print('Hellow world', end="...")

password = input('Entering your password：')
print(f'Your password is: {password}')
# <class 'str'>
print(type(password))

# to list
t1 = (100, 200, 300)
print(list(t1))
print(type(list(t1)))

# eval() -- 将字符串中的数据转换成Python表达式原本类型
str1 = '10'
str2 = '[1, 2, 3]'
str3 = '(1000, 2000, 3000)'
print(type(eval(str1)))  #int
print(type(eval(str2)))  #list
print(type(eval(str3)))  #tuple

num1, num2, str1 = 10, 0.5, 'hello world'
print(num1)
print(num2)
print(str1)
#多变量赋相同值
a = b = 10

a = 100
a += 1
# a = a + 1 = 101
print(a)

c = 10
c *= 1 + 2
# c *= 3 then c=c*3=30
print(c)

a, b, c = 1, 2, 3
print((a < b) and (b < c))  # True
print(not (a > b))          # True

a = 0
b = 1
c = 2

# and运算符，只要有一个值为0，则结果为0，否则结果为最后一个非0数字
print(a and b)  # 0
print(c and a)  # 0
print(b and c)  # 2
print(c and b)  # 1

# or运算符，只有所有值为0结果才为0，否则结果为第一个非0数字
print(a or b)  # 1
print(a or c)  # 2
print(b or c)  # 1

import random
computer = random.randint(0, 2)   #0,1,2
#print(computer)

player = int(input('Please punch：0-stone，1-scissors，2-cloth'))

# player win: p0:c1 or p1:c2 or p2:c0
if (player == 0 and computer == 1) or (player == 1 and computer == 2) or (player == 2 and computer == 0):
    print('congradulations, you are the winner!')

# draw
elif player == computer:
    print('draw')
else:
    print('Computer win!')

a = 1
b = 2

c = a if a > b else b
print(c)  #c=2

#way1(prefer): 条件判断和2取余数为0则累加计算 
i = 1
result = 0
while i <= 100:
    if i % 2 == 0:
        result += i
    i += 1

print(result)  # print 2550

# Way2：counter control 计数器累加2
i = 0
result = 0
while i <= 100:
    result += i
    i += 2

print(result)  # print 2550

# 重复打印5行
j = 0
while j <= 4:
    # 一行打印
    i = 0
    while i <= 4:
        # 一行内的星星不能换行，取消print默认结束符\n
        print('*', end='')
        i += 1
    # 每行结束要换行，这里借助一个空的print，利用print默认结束符换行
    print()  #相当于print('\n')
    j += 1

j = 1
while j <= 9:
    i = 1
    while i <= j:
        print(f'{i}*{j}={i*j}', end=' ')
        i += 1
    print()  #or print('\n')
    j += 1

str1 = 'hereiam'
for i in str1:
    if i == 'a':
        print('Do not print a！循环非正常结束，不再打印后续')
        break
    print(i)
else:
    print('循环正常结束，已全部打印')

a = ''' This is my blog, 
        welcome!
        I \'m waiting for you!'''
print(a)

name = "abcdefg"
print(name[2:5:1]) # cde
print(name[::2]) # aceg
print(name[:-1]) # abcdef
print(name[-1]) #g
print(name[-4:-1]) # def
print(name[::-1]) # gfedcba #reverse

mystr = "Welcome to this blog and have a good time and enjoy!"
print(mystr.index('and'))  # 21
print(mystr.index('and', 25, 50))  # 42
print(mystr.count('and'))  # 2

mystr = "Welcome to this blog and have a good time and enjoy!"
print(mystr.replace("and", "to"))  # Welcome to this blog to have a good time to enjoy!
print(mystr.replace("and", "to", 10))  # Welcome to this blog to have a good time to enjoy!
repstr = mystr.replace("and","to", 1)
print(repstr)  # Welcome to this blog to have a good time and enjoy!
print(mystr)   # Welcome to this blog and have a good time and enjoy!

mystr = "Welcome to this blog and have a good time and enjoy and python!"
print(mystr.split("and"))  # ['Welcome to this blog ', ' have a good time ', ' enjoy ', ' python!']
print(mystr.split("and", 2))  # ['Welcome to this blog ', ' have a good time ', ' enjoy and python!']

mychar = ['I', 'like', 'programming']
print(' '.join(mychar))  # I like programming
print('...'.join(mychar))  # I...like...programming

mystr = "welcome to this blog and have a good time and enjoy and python!"
print(mystr.capitalize())  # Welcome to this blog and have a good time and enjoy and python!

mystr = "welcome to this blog and have a good time and enjoy and python!"
print(mystr.title())  # Welcome To This Blog And Have A Good Time And Enjoy And Python!

mystr = "Welcome to this blog!"
print(mystr.ljust(30, '_'))  # Welcome to this blog!_________
print(mystr.rjust(30, '_'))  # _________Welcome to this blog!
print(mystr.center(30, '_'))  # ____Welcome to this blog!_____

alist = ['a', 'b', 'c']
print('a' in alist)  # True
print('d' not in alist)  # True

nlist = [1, 5, 2, 3, 6, 8]
nlist.sort()
print(nlist)  # [1, 2, 3, 5, 6, 8]

    alist = ['a', 'b', 'c']

    i = 0
    while i < len(alist):
        print(alist[i])
        i += 1

# or 
    for i in alist:
        print(i)

num1 = (100,)
print(type(num1)) # tuple
num2 = (100)
print(type(num2)) # int

dlist = {}  # null dictionary
dlist = {'name': 'Lucky', 'age': 2, 'gender': 'male'}
for key in dlist.keys():
    print(key)

for item in dlist.items():
    print(item)

# important
for key, value in dlist.items():
    print(f'{key} = {value}')

a1 = set()
print(type(a1)) # set
a2 = {}
print(type(a2)) # dict

a3 = {10, 20, 100}
print(a3)  # {100, 10, 20} 不是{10, 20, 100}, 这体现了集合的无序性
a3.add(100)
print(a3)  # {100, 10, 20}
a3.add('abc')
print(a3) # {100, 10, 20, 'abc'}
a3.update([100, 200, 'ab'])
print(a3) # {100, 200, 10, 'ab', 'abc', 20}
a3.update('abc')
print(a3) # {'abc', 'a', 100, 'b', 200, 10, 'ab', 'c', 20}
a3.remove('ab')
print(a3) # {'abc', 'b', 100, 200, 10, 'a', 20, 'c'}
idel = a3.pop()
print(idel) # abc
print(a3) # {'b', 100, 200, 10, 'a', 20, 'c'}

from collections.abc import Iterable
print(isinstance('abc', Iterable))  # True
print(isinstance([1,2,3], Iterable))  # True
print(isinstance({'name': 'Jack', 'age': 20}, Iterable))  # True
print(isinstance(123, Iterable))  # False

for x, y in [(1, 1), (2, 4), (3, 9)]:
    print(x, y)

list1 = [i for i in range(10)]
print(list1)  # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

# 创建0-10的偶数列表
list1 = [i for i in range(10) if i % 2 == 0]
print(list1)  # [0, 2, 4, 6, 8]

# 创建如下列表：[(1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]
list1 = [(i, j) for i in range(1, 3) for j in range(3)]
print(list1)

# 创建字典
dict1 = {i: i**2 for i in range(1, 5)}
print(dict1)  # {1: 1, 2: 4, 3: 9, 4: 16}

# 合并字典
list1 = ['name', 'age', 'gender']
list2 = ['Jack', 20, 'man']
dict1 = {list1[i]: list2[i] for i in range(len(list1))}
print(dict1)  # {'name': 'Jack', 'age': 20, 'gender': 'man'}

# 提取数据 (大于等于200的字典数据)
counts = {'MBP': 268, 'HP': 125, 'DELL': 201, 'Lenovo': 199, 'acer': 99}
result = {key: value for key, value in counts.items() if value >= 200}
print(result) # {'MBP': 268, 'DELL': 201}

list1 = ['a', 'b', 'c', 'd', 'e']
for i in enumerate(list1):
    print(i)   # (0, 'a') (1, 'b') (2, 'c')
for idx, char in enumerate(list1, start=1):
    print(f'Index: {idx}; element: {char}') 
    # Index: 1; element: a 
    # Index: 2; element: b
    # Index: 3; element: c

# add
# string
str1 = 'a'
str2 = 'b'
str3 = str1 + str2
print(str3) # ab
# list
list1 = [1, 2]
list2 = [3, 4]
list3 = list1 + list2
print(list3) # [1, 2, 3, 4]
# tumple
t1 = (1, 2)
t2 = (3, 4)
t3 = t1 + t2
print(t3) # (1, 2, 3, 4)

# copy
print('/'*10) # //////////
list1 = [10]
print(list1*10) # [10, 10, 10, 10, 10, 10, 10, 10, 10, 10]
tup = ('Hi',)
print(tup*3) # ('Hi', 'Hi', 'Hi')

def function name(parameters):
    code block

def function name(parameters):
    """ 函数说明文档 """
    code block

def print_line():
    print('-' * 20)

def print_lines(num):
    i = 0
    while i < num:
        print_line()
        i += 1

print_lines(5)

a = 0

def test1():
    # modify global variable
    global a
    a = 10

def test2():
    print(a)

test1()
test2()

def test1():
    return 10

def test2(num):
    print(num)

result = test1()
test2(result)

def test1():
    return 1
    return 2
result = test1()
print(result)   # 1 只执行了第一个return，因为return退出当前函数，导致下方的代码不执行

def test2():
    return 1,2  # 正确的多个return值的写法，返回多个数据默认元组类型
result = test2()
print(result)

# 位置参数
def welcome(name, mon, day):
    print(f'Hi {name}! Today is {mon}.{day}. Welcome!')

# 缺省参数
def welcome2(name, mon, day=28):
    print(f'Hi {name}! Today is {mon}.{day}. Welcome!')

# 包裹位置传递
def pakg(*args):
    print(args)

# 包裹关键字传递
def pakg2(**kwargs):
    print(kwargs)

# 位置参数
welcome('Jack', 'Jul', 28)
# 关键字参数
welcome(day=28, name='Jack', mon='Jul')
# 缺省参数
welcome2('Jack', 'Jul')  # Hi Jack! Today is Jul.28. Welcome!
welcome2('Jack', 'Jul', 30)  # Hi Jack! Today is Jul.30. Welcome!
# 包裹位置传递
pakg('Jack', 'Jul', 28)  # ('Jack', 'Jul', 28)
# 包裹关键字传递
pakg2(name='Jack', day=28, mon='Jul')  # {'name': 'Jack', 'day': 28, 'mon': 'Jul'}

dict1 = {'name': 'Jack', 'day': 28}
a, b = dict1
print(a) # name
print(b) # day
print(dict1[a]) # Jack
print(dict1[b]) # 28

## int引用
a = 1
b = a
print(b) # 1
print(id(a), id(b))  # 140720565232016 140720565232016 内存地址相同
a = 2
print(b) # 1,说明int类型为不可变类型
print(id(a), id(b))  # 140720565232048 140720565232016 内存地址不同
b = 3
print(a) # 2
print(id(a), id(b))  # 140720565232048 140720565232080 内存地址不同

## list引用
a = [10, 20]
b = a
print(id(a), id(b))  # 2217640153480 2217640153480 内存地址相同
a.append(30)
print(b)  # [10, 20, 30], 列表为可变类型
print(id(a), id(b))  # 2217640153480 2217640153480 内存地址相同

## 引用作为实参
def test1(a):
    print(a)
    print(id(a))
    a += a
    print(a)
    print(id(a))

# int：计算前后id值不同
b = 100
test1(b)
# list：计算前后id值相同
c = [11, 22]
test1(c)

# Way1: 引入第三个变量
a, b = 1, 2
c = 0
c = a
a = b
b = c

print(a, b)  # 2 1

# Way2: 
a, b = 1, 2
a, b = b, a
print(a, b)  # 2 1

def func1():
    return 100
print(func1)  # <function func1 at 0x0000014C26D80B88>
print(func1())  # 100

func2 = lambda: 100  # no parameter list
print(func2)  # func2 is the name address of the lambda function: <function <lambda> at 0x0000014C26D9E8B8>
print(func2())  # call lambda function: 100 

# Way1:
def func1(a, b):
    return a+b
print(func1(1,2)) 

# Way2:
func2 = lambda a,b: a+b
print(func2(1,2))

# Way3:
print((lambda a,b: a+b)(1,2))

print((lambda a,b,c=100: a+b+c)(10,20))  # 130
print((lambda a,b,c=200: a+b+c)(10,20))  # 230

func1 = lambda *args: args
print(func1('Jack',100))  # ('Jack', 100)

func2 = lambda **kwargs: kwargs
print(func2(name='Jack', score=100))  # {'name': 'Jack', 'score': 100}

func1 = lambda a,b: a if a > b else b
print(func1(20,10))  # 20

stu = [
{'name': 'Tom', 'age': 20},
{'name': 'Derek', 'age': 19},
{'name': 'Jack', 'age': 22}]

func1 = lambda x: x['name']
print(func1(stu[1]))  # Rose
stu.sort(key=func1)
print(stu)  # [{'name': 'Derek', 'age': 19}, {'name': 'Jack', 'age': 22}, {'name': 'Tom', 'age': 20}]

stu.sort(key=func1, reverse=True)
print(stu)  # [{'name': 'Tom', 'age': 20}, {'name': 'Jack', 'age': 22}, {'name': 'Derek', 'age': 19}]

def sum_num(a, b, f):
    return f(a) + f(b)

print(sum_num(-1,2,abs))  # 先求绝对值再求和: 3
print(sum_num(2.9,3.1,round))  # 先四舍五入再求和: 6

list1 = [1, 2, 3, 4, 5]
def func1(x):
    return x**2

result = map(func1, list1)
print(result)  # 内存地址： <map object at 0x0000018192FF7D48>
print(list(result))  # [1, 4, 9, 16, 25]

import functools
list1 = [1, 2, 3, 4, 5]
def func(a, b):
    return a + b
result = functools.reduce(func, list1)
print(result) # 15

list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

def func1(x):
    return x%2 == 0

result = filter(func1, list1)
print(result)  # <filter object at 0x00000188D2847E88>
print(list(result))  # [2, 4, 6, 8, 10]