Home > Backend Development > Python Tutorial > Python实现遍历数据库并获取key的值

Python实现遍历数据库并获取key的值

WBOY
Release: 2016-06-10 15:12:29
Original
1609 people have browsed it

遍历Redis数据库中有以格式为PREFIX_*的按照key-value方式存储的key,并打印其值.

遍历使用SCAN,因为KEYS PREFIX_*可能会造成Redis长时间阻塞。
查询使用pipeline减少交互,提高效率。

import redis
import hiredis

pool = redis.ConnectionPool(host='127.0.0.1', port=6379, db=0)
r = redis.Redis(connection_pool=pool)

pipe = r.pipeline()
pipe_size = 100000

len = 0
key_list = []
for key in r.scan_iter(match='PREFIX_*', count=100000):
key_list.append(key)
pipe.get(key)
 if len < pipe_size:
 len += 1
else:
 for (k, v) in zip(key_list, pipe.execute()):
 print k, v
 len = 0
 key_list = []

for (k, v) in zip(key_list, pipe.execute()):
 print k, v
Copy after login

附上其他网页的代码,参考下吧

# filename itertaorfilefolder 
import os 
import os.path

filePath = raw_input('Enter filepath : ')

#遍历文件夹 
#三个参数:分别返回1.父目录 2.所有文件夹名字(不含路径) 3.所有文件名字 
for parent ,dirnames , filenames in os.walk(filePath): 
  #输出文件夹信息 
  for dirname in dirnames: 
    print 'parent is :'+parent 
    print 'dirname is '+ dirname 
  #输出文件信息 
  for filename in filenames : 
    print 'parent is :'+parent 
    print 'filename is :' + filename 
    #输出文件路径信息 
    currentPath = os.path.join(parent,filename) 
    print 'the fulll name of the file is :'+ currentPath 
    filesize = os.path.getsize(currentPath)/1024/1024 
    print 'the file size is : %.3f MB' %(filesize) 
    #删除大于50m的文件 
    if filesize > 50: 
      delete = raw_input(' are you sure to delete &#63;') 
      if delete == 'yes': 
        os.remove(currentPath)
Copy after login

以上所述就是本文的全部内容了,希望大家能够喜欢。

Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template