1.从用户那里获取信息

name = "Alex"
print("hello"  +  name)

2.让python成为你的计算器

1 print(4+5)
2 print(3-2)
3 print(2*3)
4 print(1/3)
5 print(((2+3)/3+5)*5)
6 print(2**10)

3.python语法基本介绍

Python基本数据类型一般分为：数字、字符串、列表、元组、字典、集合这六种基本数据类型。浮点型、复数类型、布尔型(布尔型就是只有两个值的整型)、这几种数字类型。列表、元组、字符串都是序列。

print(7 + "8")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for +: 'int' and 'str'

#查看数据类型
print(type("a"))
<class 'str'>
print(type(7))
<class 'int'>
print(type(4.5))
<class 'float'>

变量存储在内存中的值，这就意味着在创建变量时会在内存中开辟一个空间。基于变量的数据类型，解释器会分配指定内存，并决定什么数据可以被存储在内存中。因此，变量可以指定不同的数据类型，这些变量可以存储整数，小数或字符。

length = 10
width = 20
area = length * width
print(area)

表达式，数字和类型转换

print(7 + 8.5)

base = 3
height = 6
area = (base * height)/2
print("The area is :" + str(area))

4.定义功能

def greeting(name, department):
      print("Welcome, " + name)
      print("You are part of " + department)

greeting("blake", "AI engineering")

5.返回值

def triangle_area(base, height):
      return base * heigth / 2

area_a = triangle_area(3, 2)
area_b = triangle_area(4, 5)
sum = area_a + area_b
print("The sum of areas is : " + str(sum))

 6.while循环

def attempt(n):
      x=0
      while(x<n):
          print("Attempt" + str(x))
          x += 1
      print("Done")

attempt(5)

#用户登录输错用户名举例
username = get_username()
while not vaild_username(username):
       print("It's not vaild name,please try again")
       username = get_username()

7.无限循环以及如何打破它们

#无限循环
while x%2 ==0:
         x =  x / 2
#方法
while x!=0 and x%2 ==0:
         x =  x / 2

8.一些循环示例

#1-10的乘积
product = 1
for n in range(1,10):
     product = product * n

print(product)

#特定间隔温度转换
def to_celsius(x):
      return (x -32)*5/9

for x in range(0,101,10):
      print(x,to_celsius(x))

9.嵌套循环

#乘法表
for x in range(1,10):
     for y in range(x,10):
          print(str(x)+ "*" +str(y)+ "=" +str(x*y),end=" ")
     print()

#比赛行程，两两对抗
teams = ["Dragons", "Wolves", "Dog", "Pandas", "Unicorns"]
for home_team in teams:
     for away_team in teams:
        if home_team != away_team:
           print(home_team + "    VS   " +away_team)

10.递归

def factorial(n):
      if n<2:
         return 1
      return n * factorial(n-1)