Python中非常实用的一些功能和函数分享

2019-10-05 08:23:54王冬梅

target = open('serial.txt','r')
myObj = pickle.load(target)

print serialized_obj
print myObj

#output
# (lp0
# S'hello'
# p1
# aI42
# a(lp2
# I1
# aS'two'
# p3
# aaS'apple'
# p4
# a.
# ['hello', 42, [1, 'two'], 'apple']

这是一个原生的Python序列化方法。然而近几年来JSON变得流行起来,Python添加了对它的支持。现在你可以使用JSON来编解码。

import json

variable = ['hello', 42, [1,'two'],'apple']
print "Original {0} - {1}".format(variable,type(variable))

# encoding
encode = json.dumps(variable)
print "Encoded {0} - {1}".format(encode,type(encode))

#deccoding
decoded = json.loads(encode)
print "Decoded {0} - {1}".format(decoded,type(decoded))

# output

# Original ['hello', 42, [1, 'two'], 'apple'] - <type 'list'="">
# Encoded ["hello", 42, [1, "two"], "apple"] - <type 'str'="">
# Decoded [u'hello', 42, [1, u'two'], u'apple'] - <type 'list'="">

这样更紧凑,而且最重要的是这样与JavaScript和许多其他语言兼容。然而对于复杂的对象,其中的一些信息可能丢失。

压缩字符
当谈起压缩时我们通常想到文件,比如ZIP结构。在Python中可以压缩长字符,不涉及任何档案文件。

import zlib

string =  """   Lorem ipsum dolor sit amet, consectetu
                adipiscing elit. Nunc ut elit id mi ultricies
                adipiscing. Nulla facilisi. Praesent pulvinar,
                sapien vel feugiat vestibulum, nulla dui pretium orci,
                non ultricies elit lacus quis ante. Lorem ipsum dolor
                sit amet, consectetur adipiscing elit. Aliquam
                pretium ullamcorper urna quis iaculis. Etiam ac massa
                sed turpis tempor luctus. Curabitur sed nibh eu elit
                mollis congue. Praesent ipsum diam, consectetur vitae
                ornare a, aliquam a nunc. In id magna pellentesque
                tellus posuere adipiscing. Sed non mi metus, at lacinia
                augue. Sed magna nisi, ornare in mollis in, mollis