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Python实现遍历数据库并获取key的值

yipeiwu_com7年前 (2020-03-06)Python基础

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

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 ?') 
      if delete == 'yes': 
        os.remove(currentPath)

以上所述就是本文的全部内容了，希望大家能够喜欢。