python字典序问题实例-Python教程-PHP中文网

python字典序问题实例

php中文网

发布： 2016-06-06 11:32:45

原创

1892人浏览过

本文实例讲述了python字典序问题，分享给大家供大家参考。具体如下：

问题描述:

将字母从左向右的次序与字母表中的次序相同,且每个字符最大出现一次..例如:a,b,ab,bc,xyz等都是升序的字符串.现对字母表A产生的所有长度不超过6的升序字符串按照字典充排列并编码如下:

1	2	..	26	27	28	...
a	b	..	z	ab	ac	..

对一个升序字符串,迅速计算出它在上述字典中的编码。

实现代码如下:

import string
all_letter = string.ascii_lowercase
def gen_dict():
  result = {}
  list_num_one = [ a_letter for a_letter in all_letter ]
  list_num_two = [ i + j for i in all_letter for j in all_letter[all_letter.find(i)+1:]]
  list_num_three = [ i + j + k for i in all_letter 
           for j in all_letter[all_letter.find(i)+1:]
           for k in all_letter[all_letter.find(j)+1:]]
  list_num_four = [ i + j + k + l for i in all_letter 
           for j in all_letter[all_letter.find(i)+1:]
           for k in all_letter[all_letter.find(j)+1:]
           for l in all_letter[all_letter.find(k)+1:]]
  list_num_five = [ i + j + k + l + m for i in all_letter 
           for j in all_letter[all_letter.find(i)+1:]
           for k in all_letter[all_letter.find(j)+1:]
           for l in all_letter[all_letter.find(k)+1:]
           for m in all_letter[all_letter.find(l)+1:]]
  list_num_six = [ i + j + k + l + m + n  for i in all_letter
      for j in all_letter[all_letter.find(i)+1:]
      for k in all_letter[all_letter.find(j)+1:]
      for l in all_letter[all_letter.find(k)+1:]
      for m in all_letter[all_letter.find(l)+1:]
      for n in all_letter[all_letter.find(m)+1:]
      ]
  for key,value in enumerate(list_num_one + list_num_two + list_num_three + list_num_four + list_num_five + list_num_six):
    result.setdefault(key+1,value)
  return result
  
my_dict = gen_dict()
value_to_get = 'abcdef'
for key,value in my_dict.iteritems():
  if value == value_to_get:
    print key

登录后复制

结果:83682　　

PHP经典实例(第二版)

PHP经典实例（第2版）能够为您节省宝贵的Web开发时间。有了这些针对真实问题的解决方案放在手边，大多数编程难题都会迎刃而解。《PHP经典实例(第2版)》将PHP的特性与经典实例丛书的独特形式组合到一起，足以帮您成功地构建跨浏览器的Web应用程序。在这个修订版中，您可以更加方便地找到各种编程问题的解决方案，《PHP经典实例(第2版)》中内容涵盖了：表单处理；Session管理；数据库交互；使用We