python小技巧——实时更新

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

创建文件夹

isExists=os.path.exists(path)
if not isExists:
os.makedirs(path)
else:
print path+'目录已存在'

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

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

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'}

字典赋值

dict = {‘’a': 1, 'b':1}
dict['c'] = dict.get('c',0) + 1
>>>dict
{ 'a':1 ,  'b': 1,  'c':1}