如何实现Python中字符串格式化输出？

print 'hello %s and %s' % ('df', 'another df')

print 'hello %(first)s and %(second)s' % {'first': 'df', 'second': 'another df'}

print('姓名是 {}，年龄是 {}'.format('Tom',20))

输出：

姓名是:Tom，年龄是:20

>>> buf = StringIO.StringIO()

>>> sprintf(buf, "A = %d, B = %s\n", 3, "foo")

>>> sprintf(buf, "C = %d\n", 5)

>>> print(buf.getvalue())

A = 3, B = foo

C = 5