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layout: post title: "Python编程6——Python实现Collatz" date: 2013-01-13 10:48 comments: true

categories: Python

前言

这个是需要更多修改的部分。Python实现Collatz序列。 本来以为比较简单，但是看了看维基百科的说明，这个居然可以出现分形，顿时冋了。 这个还需要修改啊。

Collatz序列的定义

所谓的Collatz序列是这样的一种序列：

• 对于偶数，除以2
• 对于奇数，乘以3再加上1

最后直到结果为1时结束程序。

生成Collatz序列

#this is the generator of Collatz Sequece
#we use the programe to generate it
#the Collatz Sequece is the series that has the following character:
#if the number is even , divide it with 2
#if the number it odd, multilply it with 3 and add 1 to get the final result
#if we get 1, exit the programe
#waventropy

numStr=raw_input("Enter a postive number:")
num=int(numStr)
count=0

print "Start with number:",num
print "Sequece is:",
#the ending , is to set Python put the output of print in oneline

while num > 1:
    if num%2:
        num=num*3+1
    else:
        num=num/2
    print num,",",

    count+=1

else:
    print
    print "Sequece is",count,"number long"