Python學習過程中積累的練手程式碼片段（共12個）
阿新 • • 發佈：2020-11-04
1. 方法引數與裝飾器
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# d['王五']=12
# a=(12,12);
# d[a]=123;
# print(d.get((12,12)))
# 關鍵字引數
# d={'張三':10,"趙四":11}
# def person(name,age,**kw):
# print('name:%s,age:%s,kw:%s' %(name,age,kw))
# person('張三',11,city='北京',sex='男')
# person('張三',11,**d)
# # 預設引數
# def person1(name,age,city='北京',sex='男'):
# print('name:%s,age:%s,city:%s，sex:%s' %(name,age,city,sex))
# person1('李四',20,sex='女')
# # 可變引數
# def student(*name):
# print(name)
# s=['張三','李四','王五']
# student(*s)
# # 命名參賽 命名參賽必須傳引數名
# def peron2(name,age,*,city='北京',sex='男'):
# print('name:%s,age:%s,city:%s，sex:%s' %(name,age,city,sex))
# peron2('張三',11,city='北京',sex='男')
# # 在Python中定義函式，可以用必選引數、預設引數、可變引數、關鍵字引數和命名關鍵字引數，
# # 這5種引數都可以組合使用。但是請注意，引數定義的順序必須是：必選引數、預設引數、可變引數、命名關鍵字引數和關鍵字引數。
# def count():
# fs = []
# for i in range(1, 4):
# def f():
# return i*i
# fs.append(f)
# return fs
# f1, f2, f3 = count()
# print(f1())
# print(f2())
# print(f3())
# 裝飾器
import functools
def log(text):
def dis(func):
@functools.wraps(func)
def wrapper(*age, **kw):
print('%s:%s' % (text, func.__name__))
return func(*age, **kw)
return wrapper
return dis
@log('方法名')
def sum():
print('sum')
def main():
sum()
if __name__ == '__main__':
main()
2. 類的定義以及__getattr__實現鏈式連結
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
class Student(object):
__slots__ = ('name', 'age')
def __init__(self, name, age):
self.name = name
self.age = age
def out(self):
print('name:%s,age:%s' % (self.name, self.age))
s = Student('zs', 30)
s.out()
print(dir(Student))
class Chain(object):
def __init__(self, path=''):
self._path = path
def __str__(self):
return self._path
def __getattr__(self, path):
if 'user' != path:
return Chain('%s/%s' % (self._path, path))
return lambda path: Chain('%s/%s' % (self._path, path))
print(Chain().list.user('張三').age.repo)
print(type(s))
3. android自動滑動
4. 二分法查詢，選擇排序，快速排序
# 二分法查詢
def binarySearch(attr, vaule):
start = 0
end = len(attr)
while start <= end:
middle = int((start + end) / 2)
guessValue = attr[middle]
if guessValue == vaule:
return middle
elif guessValue > vaule:
end = middle
else:
start = middle
return None
# 選擇排序
def selectSort(attr):
newArray = []
for i in range(len(attr)):
smallIndex = selectSmall(attr)
newArray.append(attr.pop(smallIndex))
return newArray
def selectSmall(attr):
small = attr[0]
smallIndex = 0
for i in range(1, len(attr)):
if attr[i] < small:
small = attr[i]
smallIndex = i
return smallIndex
# 第二種選擇排序
def selectSort2(attr):
for i in range(len(attr)):
selectSmall2(i, attr)
def selectSmall2(start, attr):
small = attr[start]
smallIndex = start
for i in range(start + 1, len(attr)):
if attr[i] < small:
small = attr[i]
smallIndex = i
attr[smallIndex] = attr[start]
attr[start] = small
# 使用遞迴求陣列的和
def recursionSum(attr):
if len(attr) < 2:
return attr[0]
else:
return attr[0] + recursionSum(attr[1:])
# 快速排序
def fastSort(attr):
if len(attr) < 2:
return attr
else:
mi = attr[0]
left = [i for i in attr[1:] if i <= mi]
right = [i for i in attr[1:] if i > mi]
return fastSort(left) + [mi] + fastSort(right)
if __name__ == '__main__':
# attr = (1, 3, 6, 9, 12, 18, 19, 20, 34, 39, 40, 41, 41, 55, 56, 60, 61, 62, 63, 64, 65, 70)
attr = [11, 30, 16, 29, 2, 13, 19, 24, 314, 39, 80, 101, 41, 55, 56, 60, 61, 62, 673, 14, 6, 7]
# selectSort(attr)
print(fastSort(attr))
5.迪克斯特拉演算法
# 迪克斯特拉演算法
# 1.建立圖
graph = {}
graph["start"] = {}
graph["start"]["a"] = 5
graph["start"]["b"] = 2
graph["a"] = {}
graph["a"]["c"] = 4
graph["a"]["d"] = 2
graph["b"] = {}
graph["b"]["a"] = 8
graph["b"]["d"] = 7
graph["c"] = {}
graph["c"]["d"] = 6
graph["c"]["fin"] = 3
graph["d"] = {}
graph["d"]["fin"] = 1
graph["fin"] = {}
# 定義無窮大
infinity = float("inf")
# 2.建立開銷表 即從起始位置到節點的開銷
costs = {}
costs["a"] = 5
costs["b"] = 2
costs["c"] = infinity
costs["d"] = infinity
costs["fin"] = infinity
# 3.建立父節點表
parents = {}
parents["a"] = "start"
parents["b"] = "start"
parents["c"] = None
parents["d"] = None
parents["fin"] = None
# 4.處理過的點
processed = []
# 5.找出未處理過最短路程的點
def find_lowest_cost_node(costs):
lowest_cost = infinity
lowest_cost_node = None
for node, cost in costs.items():
if cost < lowest_cost and node not in processed:
lowest_cost = cost
lowest_cost_node = node
return lowest_cost_node
# 6.找出起點到終點最短路程
node = find_lowest_cost_node(costs)
while node is not None:
neighbor_nodes = graph[node] # 獲取鄰居點
cost = costs[node] # 處理點到起點的位置
for n, c in neighbor_nodes.items():
new_cost = cost + c # 從起點經過處理點的路程
if new_cost < costs[n]: # 如果經過處理點的路徑 比之前的路徑短 則更新開銷表和父節點表
costs[n] = new_cost
parents[n] = node
processed.append(node)
node = find_lowest_cost_node(costs)
result = "fin"
parent = parents["fin"]
while parent != "start":
result = "%s-->%s" % (parent, result)
parent = parents[parent]
result = "start-->%s" % result
print("最短路徑:%s,最短距離:%s" % (result, costs["fin"]))
# ------------------------ 迪克斯特拉演算法 -------------------------
# graph = {} # 權重圖
# graph["start"] = {}
# graph["start"]["a"] = 6
# graph["start"]["b"] = 2
#
# graph["a"] = {}
# graph["a"]["fin"] = 1
#
# graph["b"] = {}
# graph["b"]["a"] = 3
# graph["b"]["fin"] = 5
#
# graph["fin"] = {}
#
# infinity = float("inf")
# costs = {} # 開銷表
# costs["a"] = 6
# costs["b"] = 2
# costs["fin"] = infinity
#
# parents = {} # 儲存父節點
# parents["a"] = "start"
# parents["b"] = "start"
# parents["fin"] = None
#
# processed = [] # 處理過的點
#
#
# def find_lowest_cost_node(costs):
# lowest_cost = float("inf")
# lowest_cost_node = None
# for node,cost in costs.items():
# if cost < lowest_cost and node not in processed:
# lowest_cost = cost
# lowest_cost_node = node
# return lowest_cost_node
#
#
# node = find_lowest_cost_node(costs)
# while node is not None:
# neighbor_nodes = graph[node] # 獲取處理節點鄰居節點
# cost = costs[node] # 獲取該節點到起點的距離
# for n in neighbor_nodes: # 迴圈鄰居節點
# new_cost = cost + neighbor_nodes[n] # 獲取經過處理該節點到鄰居節點的距離
# if costs[n] > new_cost:
# costs[n] = new_cost
# parents[n] = node
# processed.append(node)
# node = find_lowest_cost_node(costs)
# lujing = "fin"
# fin_ = parents["fin"]
# lujing += "<-%s" % fin_
# while fin_ != "start":
# fin_ = parents[fin_]
# lujing += "<-%s" % fin_
# print(lujing)
# print(costs["fin"])
# ------------------------ 迪克斯特拉演算法 -------------------------
6.simple_server實現簡易web
7.flask實現簡易web,支援模板
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from flask import Flask, request, render_template
app = Flask(__name__)
@app.route('/', methods=['GET'])
def home():
# return '<h1>Home</h1>'
return render_template('Home.html')
@app.route('/signin', methods=['GET'])
def logon():
# return '''<form action='/logon' method='post'>
# <p><input name='username'></p>
# <p><input name='password' type='password'></p>
# <p><button type='submit'>Log On</button></p>
# </from>'''
return render_template('form.html')
@app.route('/signin', methods=['POST'])
def toLogon():
# if request.form['username'] == 'chun' and request.form['password'] == '111111':
# return '<h3>Hello,Chun</h3>'
# return '<h3>Bad username or password</h3>'
username = request.form['username']
password = request.form['password']
if username == 'chun' and password == '111111':
return render_template('signin-ok.html', username=username)
return render_template('form.html', message='Bad username or password')
if __name__ == '__main__':
app.run()
8. 使用asyncio，aiohttp搭建簡易web
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import asyncio
from aiohttp import web
from flask import Flask, request, render_template
async def index(request):
await asyncio.sleep(0, 5)
return web.Response(body=b'''<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Home</title>
</head>
<body>
<h1>Home</h1>
</body>
</html>''', content_type='text/html')
async def init(l):
app = web.Application(loop=l)
app.router.add_route('GET', '/', index)
srv = await loop.create_server(app.make_handler(), '', 8000)
print('Server started at http://127.0.0.1:8000...')
return srv
loop = asyncio.get_event_loop()
loop.run_until_complete(init(loop))
loop.run_forever()
9. 上下文管理協議，with的使用
10. 簡易物件關係對映
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
class Field(object):
"""docstring for Filed"""
def __init__(self, name, column_type):
self.name = name
self.column_type = column_type
def __getattr__(self, name):
pass
def __str__(self):
return '<%s:%s>' % (self.__class__.__name__, self.name)
class StringField(Field):
"""docstring for StringField"""
def __init__(self, name):
super(StringField, self).__init__(name, 'varchar(100)')
class IntegerField(Field):
"""docstring for IntegerField"""
def __init__(self, name):
super(IntegerField, self).__init__(name, 'bigint')
class ModelMetaclass(type):
def __new__(cls, name, bases, attrs):
if (name == 'Model'):
return type.__new__(cls, name, bases, attrs)
print('Found model: %s' % name)
mappings = dict()
for k, v in attrs.items():
if isinstance(v, Field):
mappings[k] = v
for k in mappings.keys():
attrs.pop(k)
attrs['__mappings'] = mappings
attrs['__table__'] = name
return type.__new__(cls, name, bases, attrs)
class Model(dict, metaclass=ModelMetaclass):
"""docstring for Model"""
def __init__(self, **kw):
super(Model, self).__init__(**kw)
def __getattr__(self, key):
try:
return self[key]
except Exception as e:
raise
else:
pass
finally:
pass
class User(Model):
name = StringField('name')
email = StringField('email')
address = StringField('address')
id = IntegerField('id')
u = User(id=1, name='張三', email='[email protected]', address='北京市')
u.save()
11. 使用元類實現 namedtuple以及查詢檔案
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import os
# 查詢檔案
def selectFile(path, s):
for root, dir_names, file_names in os.walk(path):
for file_name in file_names:
if s == file_name:
print(os.path.abspath(os.path.join(root, file_name)))
return
# 使用元類實現 namedtuple
# from collections import namedtuple
# Point = namedtuple('Point', ['x', 'y'])
def tupleC(name, attr):
class Meta(type):
# 定義一個元類，採用`__call__`方法來攔截類的例項化，在例項化之前我們先把位置引數全部轉入一個叫args的元組中，
# 然後在呼叫type的`__call__`方法，從而把剛才的元組傳進去，這樣就只有一個引數了，從而無論你傳入多少個位置引數，
# 在這個步驟之後，只會出現一個引數了，成功！
def __call__(self, *args):
return type.__call__(self, args)
def init(self, args):
if len(args) != len(attr):
raise ValueError('引數數量不對')
self._value = tuple(args)
# self._attr=attr
def _getattr(self, attr):
for i, value in enumerate(attr):
if value == attr:
return self._value[i]
return tuple.__getattr__(self, attr)
def _setattr(self, attr, value):
if attr != '_value' and attr != '_attr':
raise ValueError('引數值不可變')
tuple.__setattr__(self, attr, value)
t = Meta(name, (tuple,), dict())
t.__init__ = init
t.__setattr__ = _setattr
t.__getattr__ = _getattr
t.__str__ = lambda s: '%s%s' % (name, s._value)
t.__repr__ = t.__str__
return t
def main():
# selectFile('.','ShoppeVideoActivity.java')
# a=os.walk('.')
# next(a)
# next(a)
# print(next(a))
Point = tupleC('Point', ['x', 'y', 'z'])
p = Point(5, 6, 1923)
# p.x=10
print(p.z)
print(p)
if __name__ == '__main__':
main()
12. 請求網路
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import os
from urllib import request, parse
from html.parser import HTMLParser
from html.entities import name2codepoint
# get請求
def get():
with request.urlopen('https://api.douban.com/v2/book/2129650') as f:
data = f.read()
print('Status:', f.status, f.reason)
for k, v in f.getheaders():
print('%s:%s' % (k, v))
print('Data:', data.decode('utf-8'))
def post():
print('登陸微博')
email = input('Email:')
passwd = input('Password:')
login_data = parse.urlencode([
('username', email),
('password', passwd),
('entry', 'mweibo'),
('client_id', ''),
('savestate', '1'),
('ec', ''),
('pagerefer', 'https://passport.weibo.cn/signin/welcome?entry=mweibo&r=http%3A%2F%2Fm.weibo.cn%2F')
])
req = request.Request("https://passport.weibo.cn/sso/login")
req.add_header('Origin', 'https://passport.weibo.cn')
req.add_header('User-Agent',
'Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25')
req.add_header('Referer',
'https://passport.weibo.cn/signin/login?entry=mweibo&res=wel&wm=3349&r=http%3A%2F%2Fm.weibo.cn%2F')
with request.urlopen(req, data=login_data.encode("utf-8")) as f:
print('Status:', f.status, f.reason)
for k, v in f.getheaders():
print('%s:%s' % (k, v))
print('Data:', f.read().decode('utf-8'))
class MyHTMLParser(HTMLParser):
def error(self, message):
print('error---message:%s' % message)
# Overridable -- handle start tag
def handle_starttag(self, tag, attrs):
print('handle_starttag---tag:%s,attrs:%s' % (tag, attrs))
# Overridable -- handle end tag
def handle_endtag(self, tag):
print('handle_endtag---tag:%s' % tag)
# Overridable -- handle character reference
def handle_charref(self, name):
print('handle_charref---name:%s' % name)
# Overridable -- handle entity reference
def handle_entityref(self, name):
print('handle_entityref---name:%s' % name)
# Overridable -- handle data
def handle_data(self, data):
print('handle_data---data:%s' % data)
# Overridable -- handle comment
def handle_comment(self, data):
print('handle_comment---data:%s' % data)
# Overridable -- finish processing of start+end tag: <tag.../>
def handle_startendtag(self, tag, attrs):
MyHTMLParser.handle_startendtag(self,tag,attrs)
print('handle_startendtag---tag:%s,attrs:%s' % (tag, attrs))
def getHTML():
pars=MyHTMLParser()
with request.urlopen("https://www.python.org/events/python-events/") as f:
result=f.read().decode('utf-8')
print(result)
pars.feed(result)
def main():
getHTML()
if __name__ == '__main__':
main()
以上的12個Python小例子都是我在學習Python的過程中積累的，分享給大家，希望對正在學習Python的朋友有幫助~~