python基础---递归函数真题解析

方法一。有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。
即： {'k1': 大于66 , 'k2': 小于66}
values = [11, 22, 33,44,55,66,77,88,99,90]

my_dict = {}

for value in  values:
    if value>66:
        if my_dict.has_key('k1'):
            my_dict['k1'].append(value)
        else:
            my_dict['k1'] = [value]
    else:
        if my_dict.has_key('k2'):
            my_dict['k2'].append(value)
        else:
            my_dict['k2'] = [value]
方法二。from collections import defaultdict

values = [11, 22, 33,44,55,66,77,88,99,90]

my_dict = defaultdict(list)

for value in  values:
    if value>66:
        my_dict['k1'].append(value)
    else:
        my_dict['k2'].append(value)
三。defaultdict 的用法
from collections import defaultdict
 dd = defaultdict(lambda: 'N/A')
 dd['key1'] = 'abc'
 dd['key1'] # key1存在
'abc'
dd['key2'] # key2不存在，返回默认值
'N/A'

#如下，每个小字典的name对应股票名字，shares对应多少股，price对应股票的价格
portfolio = [
    {'name': 'IBM', 'shares': 100, 'price': 91.1},
    {'name': 'AAPL', 'shares': 50, 'price': 543.22},
    {'name': 'FB', 'shares': 200, 'price': 21.09},
    {'name': 'HPQ', 'shares': 35, 'price': 31.75},
    {'name': 'YHOO', 'shares': 45, 'price': 16.35},
    {'name': 'ACME', 'shares': 75, 'price': 115.65}]
#1.计算购买每支股票的总价?
ret = map(lambda dic:{dic['name']:round(dic['share']*dic['price'],2)},portfolio)
print(list(ret))
#2.用filter过滤出，单价大于100的股票有哪些?
#方法一
ret = filter(lambda dic:True if dic['price'] > 100 else False,portfilio)
print(list(ret))
#方法二
ret = filter(lambda dic:dic['price'] > 100,portfilio)
print(list(ret))

利用递归函数找二分法
def find(l,aim,start = 0,end = None):
    end = len(l) if end is None else end
    mid_index = (end - start)//2 + start
    if start <= end:
        if l[mid_index] < aim:
            return find(l,aim,start = mid_index+1,end = end)
        elif l[mid_index] > aim:
            return find(l,aim,start = start,end = mid_index-1)
        else:
            return mid_index
    else:
        return '找不到这个值'
ret = find(l,55)
print(ret)

import re

ret=re.findall(r"\d+","1-2*(60+(-40.35/5)-(-4*3))")
print(ret) #['1', '2', '60', '40', '35', '5', '4', '3']
ret=re.findall(r"-?\d+\.\d*|(-?\d+)","1-2*(60+(-40.35/5)-(-4*3))")
print(ret) #['1', '-2', '60', '', '5', '-4', '3']
ret.remove("")
print(ret) #['1', '-2', '60', '5', '-4', '3']

1、 匹配一段文本中的每行的邮箱
      http://blog.csdn.net/make164492212/article/details/51656638

2、 匹配一段文本中的每行的时间字符串，比如：‘1990-07-12’；

   分别取出1年的12个月（^(0?[1-9]|1[0-2])$）、
   一个月的31天：^((0?[1-9])|((1|2)[0-9])|30|31)$

3、 匹配qq号。(腾讯QQ号从10000开始)  ［1,9］[0,9]{4,}

4、 匹配一个浮点数。       ^(-?\d+)(\.\d+)?$   或者  -?\d+\.?\d*

5、 匹配汉字。             ^[\u4e00-\u9fa5]{0,}$ 

6、 匹配出所有整数

import requests

import re
import json

def getPage(url):

    response=requests.get(url)
    return response.text

def parsePage(s):
    
    com=re.compile('<div class="item">.*?<div class="pic">.*?<em .*?>(?P<id>\d+).*?<span class="title">(?P<title>.*?)</span>'
                   '.*?<span class="rating_num" .*?>(?P<rating_num>.*?)</span>.*?<span>(?P<comment_num>.*?)评价</span>',re.S)

    ret=com.finditer(s)
    for i in ret:
        yield {
            "id":i.group("id"),
            "title":i.group("title"),
            "rating_num":i.group("rating_num"),
            "comment_num":i.group("comment_num"),
        }

def main(num):

    url='https://movie.douban.com/top250?start=%s&filter='%num
    response_html=getPage(url)
    ret=parsePage(response_html)
    print(ret)
    f=open("move_info7","a",encoding="utf8")

    for obj in ret:
        print(obj)
        data=json.dumps(obj,ensure_ascii=False)
        f.write(data+"\n")

if __name__ == '__main__':
    count=0
    for i in range(10):
        main(count)
        count+=25

import re
import json
from urllib.request import urlopen

def getPage(url):
    response = urlopen(url)
    return response.read().decode('utf-8')

def parsePage(s):
    com = re.compile(
        '<div class="item">.*?<div class="pic">.*?<em .*?>(?P<id>\d+).*?<span class="title">(?P<title>.*?)</span>'
        '.*?<span class="rating_num" .*?>(?P<rating_num>.*?)</span>.*?<span>(?P<comment_num>.*?)评价</span>', re.S)

    ret = com.finditer(s)
    for i in ret:
        yield {
            "id": i.group("id"),
            "title": i.group("title"),
            "rating_num": i.group("rating_num"),
            "comment_num": i.group("comment_num"),
        }


def main(num):
    url = 'https://movie.douban.com/top250?start=%s&filter=' % num
    response_html = getPage(url)
    ret = parsePage(response_html)
    print(ret)
    f = open("move_info7", "a", encoding="utf8")

    for obj in ret:
        print(obj)
        data = str(obj)
        f.write(data + "\n")

count = 0
for i in range(10):
    main(count)
    count += 25

flags有很多可选值：

re.I(IGNORECASE)忽略大小写，括号内是完整的写法
re.M(MULTILINE)多行模式，改变^和$的行为
re.S(DOTALL)点可以匹配任意字符，包括换行符
re.L(LOCALE)做本地化识别的匹配，表示特殊字符集 \w, \W, \b, \B, \s, \S 依赖于当前环境，不推荐使用
re.U(UNICODE) 使用\w \W \s \S \d \D使用取决于unicode定义的字符属性。在python3中默认使用该flag
re.X(VERBOSE)冗长模式，该模式下pattern字符串可以是多行的，忽略空白字符，并可以添加注释

import re
ret = re.search("<(?P<tag_name>\w+)>\w+</(?P=tag_name)>","<h1>hello</h1>")
#还可以在分组中利用?<name>的形式给分组起名字
#获取的匹配结果可以直接用group('名字')拿到对应的值
print(ret.group('tag_name'))  #结果 ：h1
print(ret.group())  #结果 ：<h1>hello</h1>

ret = re.search(r"<(\w+)>\w+</\1>","<h1>hello</h1>")
#如果不给组起名字，也可以用\序号来找到对应的组，表示要找的内容和前面的组内容一致
#获取的匹配结果可以直接用group(序号)拿到对应的值
print(ret.group(1))
print(ret.group())  #结果 ：<h1>hello</h1>

import random

def v_code():

    code = ''
    for i in range(5):

        num=random.randint(0,9)
        alf=chr(random.randint(65,90))
        add=random.choice([num,alf])
        code="".join([code,str(add)])

    return code

print(v_code()

# 练习一：在终端输出如下信息
#
# 小明，10岁，男，上山去砍柴
# 小明，10岁，男，开车去东北
# 小明，10岁，男，最爱大保健
# 老李，90岁，男，上山去砍柴
# 老李，90岁，男，开车去东北
# 老李，90岁，男，最爱大保健
# 老张…
class Person:
    def __init__(self,name,age,sex):
        self.name = name
        self.age = age
        self.sex = sex
    def shangshan(self):
        print('%s%d%s上山砍柴'%(self.name,self.age,self.sex))
    def drive(self):
        print('%s%d%s开车去东北'%(self.name,self.age,self.sex))
    def favorite(self):
        print('%s%d%s最爱大保健'%(self.name,self.age,self.sex))
p1 = Person('小明',23,'男')
p2 = Person('老李',32,'男')
Person.shangshan(p1)
p1.shangshan()
Person.drive(p2)
p2.drive()

from math import pi
class Arc:
    def __init__(self,r):
        self.r = r
    def area(self):
        return pi*(self.r**2)
    def perimeter(self):
        print(2*self.r*pi)
p1 = Arc(3)
print(p1.area())
p1.perimeter()
print(Arc.area(p1))
Arc.perimeter(p1)

 

class Carstore(object):
    def __init__(self):
        self.factory = Factory()
    def order(self,car_type):
            return self.factory.select_car_by_type(car_type)
class Factory(object):
    def select_car_by_type(self,car_type):
        if car_type == '索纳塔':
            return Suonata()
        elif car_type == '名图':
            return Mingtu()
        elif car_type == 'ix35':
            return Ix35()
class Car(object):
    def move(self):
        print('车在移动。。。')
    def music(self):
        print('正在播放音乐。。。')
    def stop(self):
        print('车在停止。。。')
class Suonata(Car):pass
class Mingtu(Car):pass
class Ix35(Car):pass
car_store = Carstore()
car = car_store.order('索纳塔')
car.move()
car.music()
car.stop()

 

class Dog:
    def __init__(self,name,blood,aggr,kind):
        self.name = name
        self.hp = blood
        self.aggr = aggr
        self.kind = kind
    def bite(self,person):
        person.blood -= self.aggr
class Person:
    def __init__(self,name,blood,aggr,sex):
        self.name = name
        self.blood = blood
        self.aggr = aggr
        self.sex = sex
    def attack(self,dog):
        dog.hp -= self.aggr
        if dog.hp <= 0:
            print('%s is over %s have %s xie'%(dog.name,self.name,self.blood))
        else:print('%s dadiao le %s %sdixie'%(self.name,dog.name,dog.hp))
d1 = Dog('jinlaoban',100,10,'taddy')
p1 = Person('laoli',100,10,'nan')
p1.attack(d1)
d1.bite(p1)