7.1 函数input()：接受一个参数（向用户显示的提示 或说明）

在提示的末尾，包含一个空格，与用户输入分开，
如，

 name = input('plz type your name: ')#冒号后，有空格

+= 运算符：在字符串后加一个字符串，（先加再赋值）
如，

say_hi = input("today")
say_hi += input("how are u?")

#say_hi = say_hi + 1

函数int():仅获取数值
如，

>>> age = input('how old are u?')
how old are u?1
>>> age = int(age)
>>> age > 1
False

% 求模运算符：两数相除并返回余数。(只指出余数是多少)
如，

>>> 4 % 3
1
>>> 3 % 2
1
>>> 2 % 2#整除情况下，余数为 0
0

/

7.2 while循环：满足条件则不断运行，不满足条件则为止。

num = 1
while num < 5:#数字1 < 5，就一直+1，直到 num > 5，循环结束，
    print(num)
    num += 1

运行结果：
1
2
3
4

/

让用户决定何时退出？

messages = 'what do u do?'
messages += "\ttype 'q' to end: "
message = ""
while message != 'q':#当 message 不是 q，满足条件，则一直打印，当不满足条件时，则结束。
    message = input(messages)
    print(message)

运行结果：
what do u do?   type 'q' to end: w
w
what do u do?   type 'q' to end: e
e
what do u do?   type 'q' to end: r
r
what do u do?   type 'q' to end: q
q

上面例子，结束时 q 也一同打了出来，用 if 判断去避免，

messages = 'what do u do?'
messages += "\ttype 'q' to end: "
message = ""
while message != 'q':
    message = input(messages)
    if message != 'q':
        print(message)

运行结果：
what do u do?   type 'q' to end: w
w
what do u do?   type 'q' to end: e
e
what do u do?   type 'q' to end: r
r
what do u do?   type 'q' to end: q

/
使用标志(flag)，满足多条件：
如，

messages = 'what do u do?'
messages += "\ttype 'q' to end: "
active = True#变量active设置为True，最初为活动状态，
while active:
    message = input(messages)
    if message == 'q':
        active = False
    else:
        print(message)

运行结果：
what do u do?   type 'q' to end: w
w
what do u do?   type 'q' to end: e
e
what do u do?   type 'q' to end: q

/

7.3 使用break退出循环：立即退出，不再运行余下的代码，用于控制程序流程，
如，

messages = 'what do u do?'
messages += "\ttype 'q' to end: "
while True:#以 while True 打头的循环将不断运行，直到遇见 break
    message = input(messages)
    if message == 'q':
        break
    else:
        print(message)

运行结果：
what do u do?   type 'q' to end: w
w
what do u do?   type 'q' to end: e
e
what do u do?   type 'q' to end: r
r
what do u do?   type 'q' to end: q

/

7.4 在循环中使用continue:返回循环的开头，并根据条件测试结果决定是否继续执行循环。
如，

num = 0
while num < 9:
    num += 1
    if num  % 2 == 0:
        continue

    print(num)

运行结果：
1
3
5
7
9

/

避免无限循环的正确表达：
如，

num = 1
while num < 5:
    print(num)
    num += 1#如果遗漏，循环将无限进行，

运行结果：
1
2
3
4

/

7.5 while 循环处理列表和字典：可在遍历列表的同时，对其进行需改，

unroom = ['aa','bb','cc','dd',]
inrooms = []
while unroom:
    now = unroom.pop()#使用方法pop()将列表unroom末尾元素弹出，并赋值给变量 now（开始捋一捋没进房间的人名单，）
    print(f"verifying:{now.title()}")#（捋清楚了，并打印出来，）
    inrooms.append(now)#房间门打开，开始接受
print('\nthe following verifying:')
for inroom in inrooms:
    print(inroom)

运行结果：
verifying:Dd
verifying:Cc
verifying:Bb
verifying:Aa

the following verifying:
dd
cc
bb
aa

/

使用while删除列表的所有特定值元素：
如，

nums = [1,3,5,7,9,1,1,1,]
print(nums)
while 1 in nums:
    nums.remove(1)
print(nums)

运行结果：
[1, 3, 5, 7, 9, 1, 1, 1]
[3, 5, 7, 9]

/

使用while来填充用户输入到字典：

peoples = {}#创建一个空字典，
poll_active = True#设置一个标志，检测是否继续，
while poll_active:
    name = input("what's your name: ")#收集键
    ages = input("How old are u: ")#收集值
    ages = int(ages)
    peoples[name] = ages#添加键值对信息到字典peoples 中，

    repeat = input("would u like to another person respond? (y / n)")#重复这句，问还需要其他人参加调查嘛
    if repeat == 'n':
        poll_active = False
    
    print("--- polling results ---")
    for name, ages in peoples.items():
        print(f"My name is {name.title()}, {ages} years old.")

运行结果：
what's your name: qq
How old are u: 18
would u like to another person respond? (y / n)y
--- polling results ---
My name is Qq, 18 years old.
what's your name: xx
How old are u: 21
would u like to another person respond? (y / n)n
--- polling results ---
My name is Qq, 18 years old.
My name is Xx, 21 years old.