牛顿法的实现：
在需要时对其进行少量调整应该很容易。尝试一下，告诉我们什么时候遇到困难。
from math import *
def average(a, b):
return (a + b) / 2.0
def improve(guess, x):
return average(guess, x/guess)
def good_enough(guess, x):
d = abs(guess*guess - x)
return (d < 0.001)
def square_root(guess, x):
while(not good_enough(guess, x)):
guess = improve(guess, x)
return guess
def my_sqrt(x):
r = square_root(1, x)
return r
>>> my_sqrt(16)
4.0000006366929393
注意：您将在SO或谷歌搜索（BUT）上找到有关如何使用原始输入的足够实例，如果您要计算循环，循环c=0必须在循环之外，否则您将陷入无限循环。
Quiqk又脏又脏，有很多改善方法：
from math import *
def average(a, b):
return (a + b) / 2.0
def improve(guess, x):
return average(guess, x/guess)
def square_root(guess, x, c):
guesscount=0
while guesscount < c :
guesscount+=1
guess = improve(guess, x)
return guess
def my_sqrt(x,c):
r = square_root(1, x, c)
return r
number=int(raw_input('Enter a positive number'))
i_guess=int(raw_input('Enter an initial guess'))
times=int(raw_input('How many times would you like this program to improve your initial guess:'))
answer=my_sqrt(number,times)
print 'sqrt is approximately ' + str(answer)
print 'difference between your guess and sqrt is ' + str(abs(i_guess-answer))
602392714
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