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格式化字符串／复合字段名
>>> import humansize
>>> si_suffixes = humansize.SUFFIXES[1000]
>>> si_suffixes
[‘KB‘, ‘MB‘, ‘GB‘, ‘TB‘, ‘PB‘, ‘EB‘, ‘ZB‘, ‘YB‘]
>>> ‘1000{0[0]} = 1{0[1]}‘.format(si_suffixes)
‘1000KB = 1MB‘
>>> import humansize
>>> import sys
>>> ‘1MB = 1000{0.modules[humansize].SUFFIXES[1000][0]}‘.format(sys)
‘1MB = 1000KB‘
Sys.modules 是一个保存当前python实例中搜有已导入模块的字典。模块的名字为键，模块自身为值。
>>> s = ‘‘‘finished files are the re- sults of years of scientific study combined with the experience of years. ‘‘‘ >>> s.splitlines() [‘finished files are the re-‘, ‘sults of years of scientific study combined with the‘, ‘experience of years. ‘] >>> print(s.lower()) finished files are the re- sults of years of scientific study combined with the experience of years.
>>> a_list = query.split("&")
>>> a_list
[‘user=pilgrim‘, ‘database=master‘, ‘password=PapayaWhip‘]
>>> a_list_of_list = [v.split(‘=‘,1) for v in a_list]
>>> a_list_of_list
[[‘user‘, ‘pilgrim‘], [‘database‘, ‘master‘], [‘password‘, ‘PapayaWhip‘]]
>>> a_dict = dict(a_list_of_list)
>>> a_dict
{‘password‘: ‘PapayaWhip‘, ‘database‘: ‘master‘, ‘user‘: ‘pilgrim‘}
split()－根据指定的分隔符，将字符串分隔成一个字符串列表。
dict() － 将包含列表的列表转换成字典对象
字符串的分片
>>> a_string = "My alphabet starts where your alphabet ends." >>> a_string[3:11] ‘alphabet‘ >>> a_string[3:-3] ‘alphabet starts where your alphabet en’ >>> a_string[:18] ‘My alphabet starts’ >>> a_string[18:] ‘ where your alphabet ends.‘
String VS. Bytes
Bytes对象的定义：b’ ’, eg: by = b’abcd\x65’
Bytes对象不能改变其值，但可以通过内置函数bytearry()将bytes对象转化成bytearry对象，bytearry对象的值可改变
>>> by = b‘abcd\x65‘ >>> barr = bytearray(by) >>> barr bytearray(b‘abcde‘) >>> barr[0]=102 >>> barr bytearray(b‘fbcde‘)
>>> a_string = "dive into python" >>> by = a_string.encode(‘utf-8‘) >>> by b‘dive into python‘ >>> roundtrip = by.decode(‘big5‘) >>> roundtrip ‘dive into python‘
string.encode() -- 使用某种编码方式作为参数，将字符串转化为bytes对象。
bytes.decode() -- 使用某种编码方式作为参数，将bytes对象转化成字符串对象。
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原文地址：http://www.cnblogs.com/summerlong/p/4476010.html
