第六篇：python基础_6 内置函数与常用模块

Posted 2020-10-01

本篇内容

1. 内置函数
2. 匿名函数
3. re模块
4. time模块
5. random模块
6. os模块
7. sys模块
8. json与pickle模块
9. shelve模块

 

一、 内置函数

1.定义

内置函数又被称为工厂函数。

2.常用的内置函数

（1）abs()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(abs(-1))

 （2）all()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(all([1,2,‘a‘,None]))
print(all([]))

 （3）any()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(any([]))
print(any([‘ ‘,None,False]))
print(any([‘‘,None,False]))
print(any([‘‘,None,False,1]))

 （4）bin(),oct(),hex()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(bin(10))
print(oct(10))
print(hex(10))

 （5）bytes()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

#unicode----encode----->bytes
print(‘hello‘.encode(‘utf-8‘))
print(bytes(‘hello‘,encoding=‘utf-8‘))

 （6）callable()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(callable(bytes))
print(callable(abs))

 （7）chr(),ord()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(chr(65))
print(chr(90))
print(ord(‘#‘))

 （8）int()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

x=1
print(type(x))
x=int(2)
print(type(x))

 complex()、float()、str()、list()、tuple()、dict()与int()同理

（9）set()，可变集合

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

s={1,2,3,4}
print(type(s))

 （10）frozenset()，不可变集合

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

s1=frozenset({1,2,3,4})
print(type(s1))

 （11）dir()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import sys
#sys.path
# sys.argv
print(dir(sys))

 （12）divmod()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(divmod(10,3))
print(divmod(102,20))

 （13）enumerate()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

l=[‘a‘,‘b‘,‘c‘]
res=enumerate(l)
for i in res:
    print(i)
for index,item in enumerate(l):
    print(index,item)

 （14）globals(),locals()，查看全局作用域和局部作用域

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(globals())

 （15）hash()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(hash(‘abcdefg123‘))
print(hash(‘abcdefg123‘))

 （16）help()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

def func():
    ‘‘‘
    test function
    :return:
    ‘‘‘
    pass

print(help(func))

 （17）id()，是python解释器实现的功能，只是反映了变量在内存的地址，但并不是真实的内存地址

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

x=1
print(id(x))
def func():
    pass
print(id(func))
print(func)

（18）isinstance()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

x=1
print(type(x) is int)
print(isinstance(x,int))

 （19）max(),min()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(max([1,2,3,10]))
print(max([‘a‘,‘b‘]))
print(min([1,2,3,10]))

 （20）pow()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(pow(3,2,2)) #3**2%2

 （21）repr(),str()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(type(str(1)))
print(type(repr(1)))

 （22）reversed()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

l=[1,‘a‘,2,‘c‘]
print(list(reversed(l)))
print(l)

 （23）slice()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

l=[1,2,3,4,5,6]
print(l[0:4:2])

s=slice(0,4,2)
print(l[s])

 （24）sorted()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

l=[1,10,4,3,-1]
print(sorted(l,reverse=True))

 （25）sum()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(sum([1, 2,3]))
print(sum(i for i in range(10)))

 （26）vars()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import m1
print(vars(m1) == m1.__dict__)

 （27）zip()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

s=‘helloss‘
l=[1,2,3,4,5]
print(list(zip(s,l)))

 （28）__import__()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import sys

m_name=input(‘module>>: ‘)
if m_name == ‘sys‘:
    m=__import__(m_name)
    print(m)
    print(m.path)

sys=__import__(‘sys‘)
print(sys)

 （29）round()

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

print(round(3.565,2))
print(round(3.555,2))

 

二、 匿名函数

1.定义

 匿名函数：

（1）没有名字。

（2）函数体自带return。

匿名函数的应用场景：
应用于一次性的场景，临时使用。

2.使用

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

def func(x,y,z=1):
    return x+y+z

print(func)
print(func(1,2,3))

print(lambda x,y,z=1:x+y+z)
f=lambda x,y,z=1:x+y+z
print(f)
print(f(1,2,3))

 

三、 re模块

（1）

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

print(re.findall(‘\\w‘,‘hello_ | yanglei 123‘))
print(re.findall(‘\\W‘,‘hello_ | yanglei 123‘))
print(re.findall(‘\\s‘,‘hello_ | yanglei 123 \\n \\t‘))
print(re.findall(‘\\S‘,‘hello_ | yanglei 123 \\n \\t‘))
print(re.findall(‘\\d‘,‘hello_ | yanglei 123 \\n \\t‘))
print(re.findall(‘\\D‘,‘hello_ | yanglei 123 \\n \\t‘))
print(re.findall(‘h‘,‘hello_ | hello h yanglei 123 \\n \\t‘))
print(re.findall(‘\\Ahe‘,‘hello_ | hello h yanglei 123 \\n \\t‘))
print(re.findall(‘^he‘,‘hello_ | hello h yanglei 123 \\n \\t‘))
print(re.findall(‘123\\Z‘,‘hello_ | hello h yanglei 123 \\n \\t123‘))
print(re.findall(‘123$‘,‘hello_ | hello h yanglei 123 \\n \\t123‘))
print(re.findall(‘\\n‘,‘hello_ | hello h yanglei 123 \\n \\t123‘))
print(re.findall(‘\\t‘,‘hello_ | hello h yanglei 123 \\n \\t123‘))

 （2）. [] [^]

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

#.本身代表任意一个字符
print(re.findall(‘a.c‘,‘a a1c a*c a2c abc a c aaaaaac aacc‘))

#[]内部可以有多个字符，但是本身只配多个字符中的一个
print(re.findall(‘a[0-9][0-9]c‘,‘a a12c a1c a*c a2c a c a\\nc‘,re.S))
print(re.findall(‘a[a-zA-Z]c‘,‘aac abc aAc a12c a1c a*c a2c a c a\\nc‘,re.S))
print(re.findall(‘a[^a-zA-Z]c‘,‘aac abc aAc a12c a1c a*c a2c a c a\\nc‘,re.S))
print(re.findall(‘a[\\+\\/\\*\\-]c‘,‘a-c a+c a/c aac abc aAc a12c a1c a*c a2c a c a\\nc‘,re.S))

 （3）\\：转义

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

print(re.findall(r‘a\\\\c‘,‘a\\c abc‘))

 （4）? * + {}：左边有几个字符，如果有的话，贪婪匹配

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

#?左边那一个字符有0个或者1个
print(re.findall(‘ab?‘,‘aab a ab aaaa‘))

#*左边那一个字符有0个或者无穷个
print(re.findall(‘ab*‘,‘a ab abb abbb abbbb bbbbbb‘))
print(re.findall(‘ab{0,}‘,‘a ab abb abbb abbbb bbbbbb‘))

#+左边那一个字符有1个或者无穷个
print(re.findall(‘ab+‘,‘a ab abb abbb abbbb bbbbbb‘))
print(re.findall(‘ab{1,}‘,‘a ab abb abbb abbbb bbbbbb‘))

#{n,m}左边的字符有n-m次
print(re.findall(‘ab{3}‘,‘a ab abb abbb abbbb bbbbbb‘))
print(re.findall(‘ab{2,3}‘,‘a ab abb abbb abbbb bbbbbb‘))

 （5）.* .*?

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

#.*贪婪匹配
print(re.findall(‘a.*c‘,‘a123c456c‘))

#.*?非贪婪匹配
print(re.findall(‘a.*?c‘,‘a123c456c‘))

 （6）|

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

print(re.findall(‘company|companies‘,‘Too many companies have gone bankrupt, and the next one is my company‘))
print(re.findall(‘compan|companies‘,‘Too many companies have gone bankrupt, and the next one is my company‘))

 （7）()：分组

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

print(re.findall(‘ab+‘,‘abababab123‘))
print(re.findall(‘ab+123‘,‘abababab123‘))

print(re.findall(‘ab‘,‘abababab123‘))
print(re.findall(‘(ab)‘,‘abababab123‘))
print(re.findall(‘(a)b‘,‘abababab123‘))
print(re.findall(‘a(b)‘,‘abababab123‘))
print(re.findall(‘(ab)+‘,‘abababab123‘))
print(re.findall(‘(?:ab)+‘,‘abababab123‘))

print(re.findall(‘(ab)+123‘,‘abababab123‘))
print(re.findall(‘(?:ab)+123‘,‘abababab123‘))
print(re.findall(‘(ab)+(123)‘,‘abababab123‘))

print(re.findall(‘compan(y|ies)‘,‘Too many companies have gone bankrupt, and the next one is my company‘))
print(re.findall(‘compan(?:y|ies)‘,‘Too many companies have gone bankrupt, and the next one is my company‘))

 （8）re的其他方法

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import re

print(re.findall(‘ab‘,‘abababab123‘))
print(re.search(‘ab‘,‘abababab123‘).group())
print(re.search(‘ab‘,‘12aasssdddssssssss3‘))
print(re.search(‘ab‘,‘12aasssdddsssssssab3sssssss‘).group())
print(re.search(‘ab‘,‘123ab456‘))

print(re.match(‘ab‘,‘123ab456‘))

print(re.split(‘b‘,‘abcde‘))
print(re.split(‘[ab]‘,‘abcde‘))

print(re.sub(‘xiaolan‘,‘xiaohong‘,‘xiaolan make love xiaolan xiaolan‘,1))
print(re.subn(‘xiaolan‘,‘xiaohong‘,‘xiaolan make love xiaolan xiaolan‘,1))
print(re.sub(‘(\\w+)(\\W+)(\\w+)(\\W+)(\\w+)‘,r‘\\5\\2\\3\\4\\1‘,‘Toms make love‘))
print(re.sub(‘(\\w+)( .* )(\\w+)‘,r‘\\3\\2\\1‘,‘Toms make love‘))

obj=re.compile(‘\\d{2}‘)
print(obj.search(‘abc123eeee‘).group())
print(obj.findall(‘abc123eeee‘))

 

四、time模块

模块方法

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import time

print(time.time())
print(time.strftime(‘%Y-%m-%d %X‘))

print(time.localtime())
print(time.gmtime()) #UTC
print(time.localtime().tm_mon)

print(time.localtime(123123123))
print(time.gmtime(123123123))

print(time.mktime(time.localtime()))

print(time.strftime(‘%Y‘,time.gmtime()))

‘2017-03-01‘
print(time.strptime(‘2017-03-01‘,‘%Y-%m-%d‘))

print(time.ctime(12312312))
print(time.asctime(time.gmtime()))

 

五、random模块

1.模块方法

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import random
print(random.sample([1,‘23‘,[4,5]],2))

print(random.uniform(1,3))

item=[1,3,5,7,9]
random.shuffle(item)
print(item)

2. 生成秘钥应用

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import random
def make_code(n):
    res=‘‘
    for i in range(n):
        s1=str(random.randint(0,9))
        s2=chr(random.randint(65,90))
        res+=random.choice([s1,s2])
    return res
print(make_code(10))

 

六、os模块

模块方法

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import os

print(os.listdir(‘.‘))

print(os.stat(‘m1.py‘).st_size)

print(os.sep)
print(os.linesep)
print(os.pathsep)

print([os.sep,os.linesep,os.pathsep])

res=os.system(‘dir .‘)
print(‘====?>‘,res)

print(os.path.dirname(r‘C:\\a\\b\\c\\d\\a.txt‘))
print(os.path.basename(r‘C:\\a\\b\\c\\d\\a.txt‘))
print(os.path.split(r‘C:\\a\\b\\c\\d\\a.txt‘))

print(os.stat(‘m1.py‘).st_atime)
print(os.stat(‘m1.py‘).st_size)
print(os.path.getsize(‘m1.py‘))

print(os.path.join(‘C:\\\\‘,‘a‘,‘b‘,‘c‘,‘d.txt‘))
print(os.path.join(‘C:\\\\‘,‘a‘,‘b‘,‘D:\\\\‘,‘c‘,‘d.txt‘))

print(os.path.normcase(‘c:/wiNdows\\\\system32\\\\‘)  )

print(os.path.normpath(‘c://wIndows\\\\System32\\\\../Temp/‘)  )

a=‘/Users/jieli/test1/\\\\\\a1/\\\\\\\\aa.py/../..‘
print(os.path.normpath(a))


print(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

BASE_DIR=os.path.normpath(os.path.join(
    os.path.abspath(__file__),
    ‘..‘,
    ‘..‘
)
)
print(BASE_DIR)

 

七、sys模块

模拟进度条应用

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import sys,time


def progress(percent,width=50): #51
    if percent >= 100:
        # print(‘\\r[%s] 100%%‘ %(width*‘#‘))
        percent=100
    show_str=(‘[%%-%ds]‘ %width) %(int(width*percent/100)*‘#‘)
    print(‘\\r%s %d%%‘ %(show_str,percent),file=sys.stdout,flush=True,end=‘‘)
#
total_size=1025121
recv_size=0

while recv_size < total_size:
    time.sleep(0.01) #模拟下载的网络延迟
    recv_size+=1024
    recv_per=int(100*recv_size/total_size)
    progress(recv_per,width=10)

 

八、json与pickle模块

（1）json

应用平台广泛

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import json
dic={‘name‘:‘yanglei‘,‘age‘:23}

print(type(json.dumps(dic)))

with open(‘a.json‘,‘w‘) as f:
    f.write(json.dumps(dic))

with open(‘a.json‘,‘r‘) as f:
    data=f.read()
    dic=json.loads(data)
    print(dic[‘name‘])

dic={‘name‘:‘yanglei‘,‘age‘:23}
json.dump(dic,open(‘b.json‘,‘w‘))
print(json.load(open(‘b.json‘,‘r‘))[‘name‘])

with open(‘c.json‘,‘r‘) as f:
    data=f.read()
    #[null,true,false,1]
    eval(data)

 （2）pickle

只对python有效

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import pickle

dic={‘name‘:‘yanglei‘,‘age‘:23}

print(pickle.dumps(dic))
with open(‘d.pkl‘,‘wb‘) as f:
    f.write(pickle.dumps(dic))

with open(‘d.pkl‘,‘rb‘) as f:
    dic=pickle.loads(f.read())
    print(dic[‘name‘])

dic={‘name‘:‘yanglei‘,‘age‘:23}
pickle.dump(dic,open(‘e.pkl‘,‘wb‘))

print(pickle.load(open(‘e.pkl‘,‘rb‘))[‘name‘])

def func():
    print(‘from func‘)

import json
print(json.dumps(func))

import pickle
print(pickle.dumps(func))
pickle.dump(func,open(‘func.pkl‘,‘wb‘))

 

九、shelve模块

 模块方法

#!/usr/binl/env python
#encoding: utf-8
#author: YangLei

import shelve

f=shelve.open(r‘sheve.shl‘)

f[‘yanglei‘]={‘age‘:23,‘pwd‘:‘123456‘}
f[‘xiaolan‘]={‘age‘:18,‘pwd‘:‘123456‘}
f.close()

obj=shelve.open(r‘sheve.shl‘)

print(obj[‘yanglei‘])
print(obj[‘xiaolan‘])

obj.close()

for i in obj:
    print(i,obj[i])