index
Python 3 教程
目录
pip install setuptools pip install wheel pip install twine pip show twine 在dist目录下生成gz文件 python3 setup.py sdist build 两种上传方式： python3 setup.py sdist upload 上传到pypi帐号 twine upload dist/* 或 python3 -m twine upload dist/* python3 -m twine upload --repository-url https://test.pypi.org/legacy/ dist/* 升级 python3 -m twine upload --skip-existing dist/*
no module named 'pip' 错误处理： py -2 -m ensurepip python -m ensurepip
python3安装
yum -y install bzip2-devel sqlite-devel openssl-devel readline-devel xz-devel xz-devel tk-devel gdbm-devel libffi-devel wget https://www.python.org/ftp/python/3.6.9/Python-3.6.9.tgz ./configure --prefix=/usr/local/python3 ./configure --enable-shared --prefix=/usr/local/python3 //生成动态库 make && make install ln -s /usr/local/python3/bin/python3 /usr/bin/python3 ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3 ln -s /usr/local/python3/lib/libpython3.7m.so /usr/lib/libpython3.7m.so //动态库 #vim /etc/profile export LD_LIBRARY_PATH=/lib:/usr/lib:/usr/local/lib pip3 install --upgrade pip pip3 install scrapy ln -s /usr/local/python3/bin/scrapy /usr/bin/scrapy
sqlite3安装冲突
wget https://www.sqlite.org/snapshot/sqlite-snapshot-201909031623.tar.gz ./configure --prefix=/usr/local/sqlite3 make && make install yum install sqlite-devel yum install libffi-devel yum install readline-devel yum install sqlite-devel yum install bzip2-devel yum install openssl-devel yum install gdbm-devel yum install libdbi-devel yum install ncurses-libs yum install zlib-devel yum install tkinter yum install tcl-devel tk-devel #yum install python3-tk 再安装编译python3 ln -s /usr/local/sqlite3/bin/sqlite3 /usr/bin/sqlite3 设置环境变量 echo "export LD_LIBRARY_PATH="/usr/local/sqlite3/lib"" >> /etc/bashrc 测试： python3 >import sqlite3 >sqlite3.sqlite_version
2018-03-15
Python之数据序列化（json、pickle、shelve）
>>> xInstance = X(1, 2, 3) >>> xInstance(1,2) _call_ with (1, 2)
_new,init和call,del_
__new__ 是一个静态方法，cls由解释器传值，返回参数
__init__有一个参数self，就是这个__new__返回的实例，__init__在__new__的基础上可以完成一些其它初始化的动作，__init__不需要返回值
若__new__没有正确返回当前类cls的实例，那__init__是不会被调用的，即使是父类的实例也不行
1. __init__(): 初始化某个类的一个实例。
2. __call__(): 使实例能够像函数一样被调用
3. __main__(): 命令行执行调用, 先调用__init__
4. __str__(): print实例显示
5. __del__(): 删除实例
class X(object):
def __new__(cls,*args, **kwargs):
print "new %s"%cls
return object.__new__(cls, *args, **kwargs)
def __init__(self, a, b, range):
self.a = a
self.b = b
self.range = range
def __main__(self):
print('command called!')
def __call__(self, a, b):
self.a = a
self.b = b
print('__call__ with （{}, {}）'.format(self.a, self.b))
def __str__(self):
print('x object')
def __del__(self, a, b, range):
del self.a
del self.b
del self.range
容器和生成器
class test():
def __init__(self,data=1):
self.data = data
def __next__(self):
if self.data > 5:
raise StopIteration
else:
self.data+=1
return self.data
t = test(3)
for i in range(3):
print(t.__next__())
def fib(end = 1000):
prev,curr=0,1
while curr < end:
yield curr
prev,curr=curr,curr+prev
print(list(fib()))
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987]
singleton
type() 不会认为子类是一种父类类型，不考虑继承关系。 isinstance() 会认为子类是一种父类类型，考虑继承关系。 不可变对象（immutable object）：Number（int、float、bool、complex）、String、Tuple. 采用等效于“传引用”的方式。 可变对象（mutable object）： List、dictionary.采用等效于“传值”的方式。
装饰器
代码分离，更加清晰
如果不定义wrapper, 装饰器只执行一次
def logger(fn):
def wrapper(*args,**kwargs):
if type(args[0]) != type(args[1]):
print("类型不一致请重试")
return
z = fn(*args, **kwargs)
f = open('C:\\Users\\Public\\Documents\\test.txt', 'w')
f.write(str(z))
f.close()
print("finish")
return wrapper
@logger # add1 = logger(add1)
def add(x,y):
ret = x + y
return ret
add(12,56)
类变量、实例变量、类方法、实例方法
class Foo:
class_var = '' #类变量，相当于静态变量
def __init__(self):
self._age = 0
self.instance_var = '' #实例变量
def __main__(self): #命令行调用python foo.py
print('usage command line!')
@classmethod
def class_method(cls,parameter):#相当于静态类，cls代表类
print(cls.instance_var)
print(class_var)
@staticmethod
def statis_method(paramter):
print(self.instance_var) #不能访问
print(class_var) #不能访问
def method(self,parameter): #实例类，self代表当前类实例
print(Object.class_var)
print(self,instance_var)
@property
def age(self):
return self._age;
@age.setter
def age(self, value):
if isinstance(value,str):
self._age = Decimal(value)
if isinstance(value, Decimal):
self._age = value
@age.deleter
def age(self):
raise AttributeError("cannot delete attribute")
foo = Foo()
print(foo.age)
foo.age = 12
del foo.age
class A:
v = 22;
a = A()
a.v = 13
print(A.v) #22
print(a.v) #13
del a.v
print(a.v) #22
xpath
from lxml import etree
import requests
html = requests.get('http://www.lzu.edu.cn').content.decode('utf-8')
dom_tree = etree.HTML(html)
links = doc_tree.xpath('//img/@src')
for item in links:
print(item)
//代表相对路径，匹配可以是任意深度的节点
/ 代表绝对路径，故对于网页来说，匹配从/html开始
“/html/body/div[@id='main']”
div[text()='hello']
"li[2]" 表示取得第二个li节点
”/html/body/*/span” “*”可以代替所有的节点名
“following-sibling::ul” 就是下一个ul节点
同时装Python3和Python2
CentOS7安装pip 1.yum -y install epel-release 2.yum install python-pip 3.pip install --upgrade pip ***for windows*** py -2 hello.py py -3 hello.py py -2 -m pip install XXXX py -3 -m pip install XXXX #! python2 # coding: utf-8 #! python2 #! python3 分别表示该代码文件第一行使用Python2或者Python3解释运行 py hello.py 直接运行 ***for linux*** 如果仅安装 python2 pip install sth # 如果安装有 python3, 则需要明确 pip 版本 py -2 -m pip install sth py -3 -m pip install sth
install pip for python3.x
1.首先安装setuptools wget --no-check-certificate https://pypi.python.org/packages/72/c2/c09362ab29338413ab687b47dab03bab4a792e2bbb727a1eb5e0a88e3b86/setuptools-39.0.1.zip#md5=75310b72ca0ab4e673bf7679f69d7a62 tar -zxvf setuptools-19.6.tar.gz cd setuptools-19.6.tar.gz python3 setup.py build python3 setup.py install 2.安装pip wget --no-check-certificate https://pypi.python.org/packages/c4/44/e6b8056b6c8f2bfd1445cc9990f478930d8e3459e9dbf5b8e2d2922d64d3/pip-9.0.3.tar.gz#md5=b15b33f9aad61f88d0f8c866d16c55d8 tar -zxvf pip-8.0.2.tar.gz cd pip-8.0.2 python3 setup.py build python3 setup.py install
显示双缓冲
def OnPaint(self, event):
if _plat.startswith('linux'):
dc = wx.PaintDC(self)
dc.Clear()
elif _plat.startswith('darwin'):
pass
elif _plat.startswith('win'):
if USE_BUFFERED_DC:
dc = wx.BufferedPaintDC(self, self._Buffer)
else:
dc = wx.PaintDC(self)
dc.DrawBitmap(self._Buffer, 0, 0)
dc.Clear()