python语法练习_python语法练习

简单的需求，获取重复次数最多的数据

@沛公

import random

_dict ={0:0,}

for i in range(1,1000000):

rd_num = random.randrange(0,999,1)

if rd_num in _dict:

_dict[rd_num] = _dict[rd_num]+1

else:

_dict[rd_num] = 1

#print(rd_num)

print(_dict)

items = _dict.items();

print(items[0:10])

items = sorted(items, lambda x,y:cmp(x[1],y[1]),reverse=True)

print(items[0:10])

4.0g 虚拟机测试 100w数据0.6s 。。。 一般了 后续添加sqlite

import sqlite3

import random

_MAX_VALUE = 100

_DATA_CNT = 1000000

conn = sqlite3.connect(‘test.db‘)

cur = conn.cursor()

def got_cnt(x):

cur.execute(‘‘‘SELECT times FROM sorted WHERE value=%s;‘‘‘ % x)

already = cur.fetchall()

length = len(already)

if length is not 0:

length = already[0][0];

#print(‘search for %s Fond %s‘ % (x,length))

return length

cur.execute(‘‘‘CREATE TABLE ramdon_data

(id INTEGER PRIMARY KEY NOT NULL,value INTEGER);‘‘‘)

cur.execute(‘‘‘CREATE TABLE sorted

(id INTEGER PRIMARY KEY NOT NULL,value INTEGER, times INTEGER);‘‘‘)

print("create ok")

for i in range(1,_DATA_CNT):

rd_num = random.randrange(0,_MAX_VALUE,1)

#print(rd_num)

cur.execute(‘‘‘INSERT INTO ramdon_data(value) VALUES

(%s);‘‘‘ % rd_num)

conn.commit();

print("data ready")

cur.execute(‘‘‘SELECT * FROM ramdon_data;‘‘‘)

ans = cur.fetchall()

for d in ans:

#print(d)

value = d[1];

times = got_cnt(d[1]) + 1

if times is 1:

cur.execute(‘‘‘INSERT INTO

sorted(value,times) VALUES(%s,%s);‘‘‘ % (value,times))

else:

cur.execute(‘‘‘UPDATE sorted

SET times=%s WHERE value=%s;‘‘‘ % (times,value))

conn.commit();

print("calc ready")

cur.execute(‘‘‘SELECT * FROM sorted ORDER BY times;‘‘‘);

ans = cur.fetchall();

print(‘‘‘

len is %s‘‘‘ % len(ans))

for d in ans:

print(d)

conn.close();

加了sqlite之后，慢多了 100w数据 30s。。。 当然 跟我毫无节操的读写数据有关系。无论如何。sqlite和python以及sql算是入门了

原文：http://my.oschina.net/mummy108/blog/476841