提高级

#二分开方
x = 2
low = 0.0
high = x
guess = (low+high)/2
while abs(guess**2-x) >1e-4:
    if guess**2 >x:
        high = guess
    else:
        low = guess
    guess = (low +high) /2
print (guess)


1.4141845703125

#局部变量，全局变量
x = 1
def f():
    x = 2
    print(x)
f()
print(x)

2
1

 1 x = 1
 2 def f():
 3     global x#x为全局变量
 4     x = x+1
 5     print(x)
 6 f()
 7 print(x)
 8 
 9 2
10 2