# python常用知识点汇总

1、set基本数据类型

a、set集合，是一个无序且不重复的元素集合

class set(object):
“””
set() -> new empty set object
set(iterable) -> new set object
build an unordered collection of unique elements.
“””
def add(self, *args, **kwargs): # real signature unknown
“””
add an element to a set，添加元素
this has no effect if the element is already present.
“””
pass
def clear(self, *args, **kwargs): # real signature unknown
“”” remove all elements from this set. 清楚内容”””
pass
def copy(self, *args, **kwargs): # real signature unknown
“”” return a shallow copy of a set. 浅拷贝 “””
pass
def difference(self, *args, **kwargs): # real signature unknown
“””
return the difference of two or more sets as a new set. a中存在，b中不存在
(i.e. all elements that are in this set but not the others.)
“””
pass
def difference_update(self, *args, **kwargs): # real signature unknown
“”” remove all elements of another set from this set. 从当前集合中删除和b中相同的元素”””
pass
def discard(self, *args, **kwargs): # real signature unknown
“””
remove an element from a set if it is a member.
if the element is not a member, do nothing. 移除指定元素，不存在不保错
“””
pass
def intersection(self, *args, **kwargs): # real signature unknown
“””
return the intersection of two sets as a new set. 交集
(i.e. all elements that are in both sets.)
“””
pass
def intersection_update(self, *args, **kwargs): # real signature unknown
“”” update a set with the intersection of itself and another. 取交集并更更新到a中 “””
pass
def isdisjoint(self, *args, **kwargs): # real signature unknown
“”” return true if two sets have a null intersection. 如果没有交集，返回true，否则返回false”””
pass
def issubset(self, *args, **kwargs): # real signature unknown
“”” report whether another set contains this set. 是否是子序列”””
pass
def issuperset(self, *args, **kwargs): # real signature unknown
“”” report whether this set contains another set. 是否是父序列”””
pass
def pop(self, *args, **kwargs): # real signature unknown
“””
remove and return an arbitrary set element.
raises keyerror if the set is empty. 移除元素
“””
pass
def remove(self, *args, **kwargs): # real signature unknown
“””
remove an element from a set; it must be a member.
if the element is not a member, raise a keyerror. 移除指定元素，不存在保错
“””
pass
def symmetric_difference(self, *args, **kwargs): # real signature unknown
“””
return the symmetric difference of two sets as a new set. 对称交集
(i.e. all elements that are in exactly one of the sets.)
“””
pass
def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
“”” update a set with the symmetric difference of itself and another. 对称交集，并更新到a中 “””
pass
def union(self, *args, **kwargs): # real signature unknown
“””
return the union of sets as a new set. 并集
(i.e. all elements that are in either set.)
“””
pass
def update(self, *args, **kwargs): # real signature unknown
“”” update a set with the union of itself and others. 更新 “””
pass

b、数据类型模块举例

se = {11,22,33,44,55}
be = {44,55,66,77,88}
# print(se) #添加元素，不能直接打印！
#
#
#
# se.clear()
# print(se) #清除se集合里面所有的值，不能清除单个
#
#
#
# ce=be.difference(se) #se中存在，be中不存在的值，必须赋值给一个新的变量
# print(ce)
#
#
# se.difference_update(be)
# print(se) #在se中删除和be相同的值，不能赋值给一个新的变量，先输入转换，然后打印，也不能直接打印！
# print(se) #移除指定元素，移除不存在的时候，不会报错
# se.remove(11)
# print(se) #移除指定的元素，移除不存在的会报错
# se.pop()
# print(se) #移除随机的元素
#
#
# ret=se.pop()
# print(ret) #移除元素，并且可以把移除的元素赋值给另一个变量
# ce = se.intersection(be)
# print(ce) #取出两个集合的交集（相同的元素）
# se.intersection_update(be)
# print(se) #取出两个集合的交集，并更新到se集合中
# ret = se.isdisjoint(be)
# print(ret) #判断两个集合之间又没有交集，如果有交集返回false，没有返回true
# ret=se.issubset(be)
# print(ret) #判断se是否是be集合的子序列，如果是返回true，不是返回flase
# ret = se.issuperset(be)
# print(ret) #判断se是不是be集合的父序列，如果是返回true，不是返回flase
# ret=se.symmetric_difference(be)
# print(ret) #对称交集，取出除了不相同的元素
# se.symmetric_difference_update(be)
# print(se) #对称交集，取出不相同的元素并更新到se集合中
# ret = se.union(be)
# print(ret) #并集，把两个元素集合并在一个新的变量中

2、深浅拷贝

a、数字和字符串

import copy
# ######### 数字、字符串 #########
n1 = 123
# n1 = “i am alex age 10”
print(id(n1))
# ## 赋值 ##
n2 = n1
print(id(n2))
# ## 浅拷贝 ##
n2 = copy.copy(n1)
print(id(n2))
# ## 深拷贝 ##
n3 = copy.deepcopy(n1)
print(id(n3))

b、其他基本数据类型

1、赋值

n1 = {“k1”: “zhangyanlin”, “k2”: 123, “k3”: [“aylin”, 456]}
n2 = n1

2、浅拷贝

import copy
n1 = {“k1”: “zhangyanlin”, “k2”: 123, “k3”: [“aylin”, 456]}
n3 = copy.copy(n1)

3、深拷贝

3、函数

.函数的定义主要有如下要点：

def：表示函数的关键字

1、返回值

def 发送短信():

if 发送成功:
return true
else:
return false
while true:
# 每次执行发送短信函数，都会将返回值自动赋值给result
# 之后，可以根据result来写日志，或重发等操作
result = 发送短信()
if result == false:

# ######### 定义函数 #########

# name 叫做函数func的形式参数，简称：形参
def func(name):
print name

# ######### 执行函数 #########
# ‘zhangyanlin’ 叫做函数func的实际参数，简称：实参
func(‘zhangyanlin’)

def func(name, age = 18):

print “%s:%s” %(name,age)

# 指定参数
func(‘zhangyanlin’, 19)
# 使用默认参数
func(‘nick’)

def func(*args):
print args
# 执行方式一
func(11,33,4,4454,5)
# 执行方式二
li = [11,2,2,3,3,4,54]
func(*li)

def func(**kwargs):
print args
# 执行方式一
func(name＝’wupeiqi’,age=18)
# 执行方式二
li = {‘name’:’wupeiqi’, age:18, ‘gender’:’male’}
func(**li)

def func(*args, **kwargs):
print args
print kwargs

def email(p,j,k):
import smtplib
from email.mime.text import mimetext
set = true
try:
msg = mimetext(‘j’, ‘plain’, ‘utf-8’) #j 邮件内容
msg[‘subject’] = “k” #k主题
server = smtplib.smtp(“smtp.126.com”, 25)
server.sendmail(‘wptawy@126.com’, [p], msg.as_string())
server.quit()
except:
set = false
return true
formmail = input(“请你输入收件人邮箱：”)
zhuti = input(“请您输入邮件主题：”)
neirong = input(“请您输入邮件内容：”)
aa=email(formmail,neirong,zhuti)
if aa:
print(“邮件发送成功!”)
else:
print(“邮件发送失败!”)

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