【Python】pickle 与 write

 

注：load后不影响持久化文件；F.write(str)，把str写到文件F中，write()并不会在str后加一个换行符。

执行结果：

pickle_sample.txt如下：

write_sample.txt如下：

 

 

#!/usr/bin/env python
#-*- coding: utf-8 -*-
import cPickle as pickle
import random
import os
import time

Length = 100 * 1000
print "Length is %d" %Length

def main():
    d = {}
    a = []
    for i in range(Length):
        a.append(random.randint(0, 255))
    d["a"] = a
    #print "d is %s" %d
    #print "a is %s" %a
    print "dumping..."
    
    #time.time()时间戳，返回从1970/01/01以来的秒数，这是一个浮点数
    t1 = time.time()
    #wb 以二进制写模式打开
    pickle.dump(d, open("tmp1.dat", "wb"), True)
    print "tmp1 dump1: %.3fs" %(time.time() - t1)

    t1 = time.time()
    #w 以写方式打开
    pickle.dump(d, open("tmp2.dat", "w"))
    print "tmp2 dump2: %.3fs" %(time.time() - t1)

    t1 = time.time()
    open("tmp3.dat", "wb").write("%s" %d)
    print "tmp3 write1: %.3fs" %(time.time() - t1)

    s1= os.stat("tmp1.dat").st_size
    s2= os.stat("tmp2.dat").st_size
    s3= os.stat("tmp3.dat").st_size
    #%%百分号标记
    print "tmp1.size is %d, tmp2.size is %d, tmp3.size is %d, tmp1.size/tmp2.size is %.2f%%" %(s1, s2, s3, 100.0 * s1/s2)
    print "loading..."

    t1 = time.time()
    #rb 以二进制读模式打开
    obj1 = pickle.load(open("tmp1.dat", "rb"))
    print "tmp1 load1: %.3fs" %(time.time() - t1)

    t1 = time.time()
    #r 以读模式打开
    obj2 = pickle.load(open("tmp2.dat", "r"))
    print "tmp2 load2: %.3fs" %(time.time() - t1)

    t1 = time.time()
    f = open("tmp3.dat", "r")
    print "tmp3 open: %.3fs" %(time.time() - t1)
    f.close()

if __name__ == "__main__":
    main()

 输出：