留存率计算

import psycopg2
import subprocess

#dicta = {}
lista = []
for date in range(6,284):
    date_day = date
    date_day_ago = date + 1
    day_ago = subprocess.check_output('date -d "{0} days ago" +%Y%m%d'.format(date_day_ago),shell=True)
    day = subprocess.check_output('date -d "{0} days ago" +%Y%m%d'.format(date_day),shell=True)   # check_output返回的类型为byte
    dicta = {'20160902\n':str(day_ago,encoding = "utf-8")}
    lista.append(dicta)





conn = psycopg2.connect(database="cygnus",user="cygnus",password="147852",host="192.168.1.127",port="5432")
cur = conn.cursor()
for x in lista:
    for item in x:
        #print(item.split('\n')[0],x[item].split('\n')[0])
        cur.execute("SELECT count(DISTINCT andid) from biz.task_req_{0} WHERE EXISTS (SELECT 1 FROM biz.task_req_{1} WHERE andid=biz.task_req_{0}.andid) and channel_id like'%012090'".format(item.split('\n')[0],x[item].split('\n')[0]))  # bytes to strings
        fenzi = cur.fetchall()
        cur.execute("SELECT count(DISTINCT andid) from biz.task_req_{0} where channel_id like '%012090'".format(x[item].split('\n')[0]))
        fenmu = cur.fetchall()
        print(item.split('\n')[0],x[item].split('\n')[0],end=' ')
        for xitem in fenzi:


            for xxitem in xitem:
                for yitem in fenmu:
                    for yyitem in yitem:
                        try:
                            print(xxitem/yyitem*100,'%')
                        except ZeroDivisionError:
                            print(0)
conn.close()