python小技巧——实时更新_python funcanimation实时更新数据

获取所有目录及文件

for root, dirs, files in os.walk(os.getcwd()):  
    print(root) #当前目录路径  
    print(dirs) #当前路径下所有子目录  
    print(files) #当前路径下所有非目录子文件 
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创建文件夹

isExists=os.path.exists(path)
if not isExists:
    os.makedirs(path) 
else:
    print path+'目录已存在'
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获取当前路径下所有目录及文件

import glob    
glob.glob('C:\\snow\\*.*')  #获取目录[C:\\snow\\]下面所有的文件
glob.glob('C:\\snow\\*.*')  #获取目录[C:\\snow\\]下面所有.txt文件
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数据库连接

import os, sys
import pymysql
class mySql(object):
    def __init__(self):
        self.Conn=None
        self.Cursor=None

    def conn(self):
        try:
            self.Conn = pymysql.connect(host='localhost',user='root',passwd='19940512',db='snow')
            self.Cursor = self.Conn.cursor()
        except Exception as e:
            print (e)

    def closeconn(self):
        if self.Conn:
            if self.Cursor:
                self.Cursor.close()
            self.Conn.close()

    def getDotInfo(self,table, num, offset,):
        rows=0;
        try:
            self.conn()
            sql='select T_Longitude,T_Latitude,T_Speed,T_Heading,T_TargetID,T_UTCTime from %s limit %r offset %r' % (table, num, offset)
            #print(sql) 
            n = self.Cursor.execute(sql)
            rows = self.Cursor.fetchall()
        except Exception as e:
            pass
        self.closeconn()
        return rows
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python2与python3兼容方法

https://www.zhihu.com/question/21653286
https://zhuanlan.zhihu.com/p/21261875
https://www.cnblogs.com/zanjiahaoge666/p/7413419.html

常用的模块
numpy,matplotlib,pandas,scipy —— 数据挖掘与分析的基础
scikit-learn —— 数据挖掘与分析

字典key与value互换

>>> a_dict = {'a': 1, 'b': 2, 'c': 3}
>>> {value:key for key, value in a_dict.items()}
{1: 'a', 2: 'b', 3: 'c'}
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字典赋值

dict = {‘’a': 1, 'b':1}
dict['c'] = dict.get('c',0) + 1
>>>dict
{ 'a':1 ,  'b': 1,  'c':1}
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采样(LDA用到了)
[numpy]random.choice()随机选取内容
https://blog.csdn.net/autoliuweijie/article/details/51982514