字符格式化
1、字符串
>>> print "My name is %s" %("zhang")
My name is zhang
>>>
2、整数：
>>> print "my age id %d" %(25)
my age id 25
3、浮点数：
>>> print "her height is %f m" %(1.60)
her height is 1.600000m
>>>
4、浮点数：指定几位小数
>>> print "her height is %.2f m" %(1.60)
her height is 1.60 m
5、指定占位宽度：
>>> print "her height is %5.2f m" %(1.60)
her height is 1.60 m
>>> print "her height is %10.2f m" %(1.60)
her height is 1.60 m
6、指定占位符宽度（左对齐）-
>>> print "her height is %-5.2f m" %(1.60)
her height is 1.60 m
>>> print "her height is %-8.2f m" %(1.60)
her height is 1.60 m
>>>+时右对齐 +号代表无论正数还是负数都要写符号
>>> print "her height is %+5.2f m" %(1.60)
her height is +1.60 m
>>> print "her height is %+8.2f m" %(1.60)
her height is +1.60 m
>>>
7、指定占位符，只能用0代替
>>> print "her height is %+08.2f m" %(1.60)
her height is +0001.60 m
8、综合：
>>> print "My name is %15s,age is %-.4d,height is %5.2f" %("zhang",24,1.6)
My name is zhang,age is 0024,height is 1.60
>>> print "My name is %15s,age is %-04d,height is %5.2f" %("zhang",24,1.6)
My name is zhang,age is 24 ,height is 1.60
>>> print "My name is %15s,age is %04d,height is %5.2f" %("zhang",24,1.6)
My name is zhang,age is 0024,height is 1.60
>>> print "My name is %-15s,age is %04d,height is %5.2f" %("zhang",24,1.6)
My name is zhang ,age is 0024,height is 1.60
9、八进制和十六进制
>>> "%#o" % 123
'0173'
>>> "%#x" % 123
'0x7b'
>>>
10、将字典类型的参数提供给格式化操作符
>>> 'There are %(howmany)d %(lang)s Quotation Symbols' % \
... {"lang":'python',"howmany":3}
'There are 3 python Quotation Symbols'
>>>
