牛客网初级项目课第一节

谁践踏了优雅 2022-06-07 13:17 255阅读 0赞

牛客网初级项目课第一节

GitHub/BitBucket

GitHub免费的服务都要公开

如果代码不想公开，并且不想付费的话，可以选择BitBucket。

Python为什么用2.0不用3.0？

因为在2.0中有很多类库，并且与3.0差别不大。

例子:

安装beautifulsoup4和request

爬取糗事百科的内容:

#coding=utf-8
    
    import requests
    from bs4 import BeautifulSoup
    
    content=requests.get('http://www.qiushibaike.com').content
    soup=BeautifulSoup(content,'html.parser')
    
    for div in soup.find_all('div',{'class':'content'}):
        print div.text.strip()

输出的是内容

#coding=utf-8
    
    import requests
    import random
    import re
    from bs4 import BeautifulSoup
    
    def qiushibaike():
        content=requests.get('http://www.qiushibaike.com').content
        soup=BeautifulSoup(content,'html.parser')
    
        for div in soup.find_all('div',{'class':'content'}):
            print div.text.strip()
    
    
    def demo_string():
        stra='hello world world'
        #首字母大写，其余小写
        print stra.capitalize()
        #替换所有的world为nowcoder
        print stra.replace('world','nowcoder')
        strb='   \n\r hello nowcoder \r\n'
        #去掉左边的空格和回车
        print 1,strb.lstrip()
        #去掉右边的空格和回车
        print 2,strb.rstrip()
        strc='hello w'
        print 3,strc.startswith('hel')
        print 4,strc.endswith('x')
        print 5,stra+strb+strc
        print 6,len(strc)
        print 7,'-'.join(['a','b','c'])
        print 8,strc.split(' ')
        print 9,strc.find('ello')
    
    def demo_operation():
        print 1,1+2,5/2,5*2,5-2
        print 2,True, not True
        print 3,1<2,5>2
        print 4,2<<3
        print 5,5|3,5&3,5^3
        x=2
        y=3.3
        print x,y,type(x),type(y)
    
    
    def demo_buildinfunction():
        print 1,max(2,1),min(5,3)
        print 2,len('xxx'),len([1,2,3])
        print 3,abs(-2)
        print 4,range(1,10,3)
        print 5,dir(list)
        x=2
        print 6,eval('x+3*x')
        print 7,chr(65),ord('a')
        print 8,divmod(11,2)
    
    def demo_controlflow():
        score=65
        if score>99:
            print 1,'A'
        elif score>60:
            print 2,'B'
        else:
            print 3,'C'
        while score<100:
            print score
            score+=10
        score=65
    
        #continue,break,pass
        for i in range(0,10,2):
            if i==0:
                pass #do special什么也不做
                # print 3,i
            if i<5:
                continue
            print 3,i
            if i==6:
                break
    
    
    def demo_list():
        lista=[1,2,3] #vector ArrayList
        print 1,lista
        listb=['a',1,'c',1.1]
        print 2,listb
        lista.extend(listb)
        print 3,lista
        print 4,len(lista)
        print 5,'a' in listb
        lista=lista+listb
        print 6,lista
        listb.insert(0,'www')
        print 7,listb
        listb.pop(1)
        print 8,listb
        listb.reverse()
        print 9,listb
        print 10,listb[0],listb[1]
        listb.sort()
        print 11,listb[0],listb[1]
        listb.sort(reverse=True)
        print 12,listb
        print 13,listb*2
        print 14,[0]*14
        tuplea=(1,2,3)
        listaa=[1,2,3]
        listaa.append(4)
        print 15,listaa
    
    def add(a,b):
        return a+b
    def sub(a,b):
        return a-b
    
    #类似于HashMap
    def demo_dict():
        dicta={4:16,1:1,2:4,3:9}
        print 1,dicta
        print 2,dicta.keys(),dicta.values()
        print 3,dicta.has_key(1),dicta.has_key('3')
        for key,value in dicta.items():
            print 'key-value:',key,value
        #类似于函数指针
        dictb={'+':add,'-':sub}
        print 4,dictb['+'](1,2)
        print 5,dictb.get('-')(15,3)
        dictb['*']='x'
        print dictb
        dicta.pop(4)
        print 6,dicta
    
    #集合
    def demo_set():
        lista=[1,2,3]
        seta=set(lista)
        setb=set((2,3,4))
        print 1,seta
        # seta.add(4)
        # print 2,seta
        print 3,seta.intersection(setb),seta&setb
        print 4,seta|setb,seta.union(setb)
        print 5,seta-setb
        seta.add(1)
        print 6,seta
    
    class User:
        type='USER'
        def __init__(self,name,uid):
            self.name=name
            self.uid=uid
        def __repr__(self):
            return ' im '+self.name+' '+str(self.uid)
    
    class Admin(User):
        type = 'ADMIN'
        def __init__(self,name,uid,group):
            User.__init__(self,name,uid)
            self.group=group
        def __repr__(self):
            return ' im '+self.name+' '+str(self.uid)+' '+self.group
    
    class Guest(User):
        def __init__(self,name,uid):
            User.__init__(self, name, uid)
        def __repr__(self):
            return ' im guest '+self.name+' '+str(self.uid)
    def create_user(type):
        if type=='USER':
            return User('u1',1)
        elif type=='ADMIN':
            return Admin('a1',101,'g1')
        else:
            return Guest('g1',100)
    
    #异常
    def demo_exception():
        try:
            print 2/1
            raise Exception('Raise Error','Nowcoder')
        except Exception as e:
            print 'error',e
        finally:
            print 'clean up'
    
    
    #随机数
    def demo_random():
        #1-100
        random.seed(1)
        #x=prex*10007%xxxx
        #prex=x 幂等性
        print 1,int(random.random()*100)
        print 2,random.randint(0,200)
        print 3,random.choice(range(0,100,10))
        print 4,random.sample(range(0,100),4)
    
        a=[1,2,3,4,5]
        random.shuffle(a)
        print 5,a
    
    
    def demo_re():
        str='abc123def12gh15'
        '''
        \d数字
        \D非数字
        \s 空格,\r\t
        \S 
        \w [0-9][a-z][A-Z]
        \W
        + 至少匹配1次
        * 至少匹配0次
        '''
        p1=re.compile('[\d]+')
        p2=re.compile('\d')
        print 1,p1.findall(str)
        print 2,p2.findall(str)
    
        str='a@163.com;b@gmail.com;c@qq.com;e@163.com;z@qq.com'
        p3=re.compile('[\w]+@[163|qq]+\.com')
        print p3.findall(str)
    
        str='<html><h>title</h><body>xxx</body></html>'
        p4=re.compile('<h>[^<]+</h>')
        print 4,p4.findall(str)
    
        p4 = re.compile('<h>([^<]+)+</h><body>([^<]+)</body>')
        print 5, p4.findall(str)
    
        str='xx2016-06-11yy'
        p5=re.compile('\d{4}-\d{2}-\d{2}')
        print p5.findall(str)
    
    if __name__=='__main__':
        demo_re()
        # demo_random()
        # demo_exception()
        # user1=User('u1',1)
        # print user1
        # admin1=Admin('a1',101,'g1')
        # print admin1
        #
        # print create_user('ANDJ')
        # print 'hello nowcoder'
        #comment
        # demo_string()
        # demo_operation()
        # demo_buildinfunction()
        # demo_controlflow()
        # demo_list()
        # demo_dict()
        # demo_set()