python3.7 初学整理

the_world_is_flat=False
if the_world_is_flat:
    print ("Be careful not to fall off!")
else:
    print ("No!")

print(2+2)
print(8/5)
print(8/2) # //忽略小数部分

print(5**2) #乘方 5的2次方

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

print(‘C:\some\name‘)
print(r‘C:\some\name‘)

str="pyt"
print(str+"hon")

num=float(input("请输入一个数字"))
if num>=0:
    if num==0:
        print ("零")
    else:
        print ("正数")
else:
    print ("负数")