python中%s和%r - 爱码网

%r用rper()方法处理对象

%s用str()方法处理对象

有些情况下，两者处理的结果是一样的，比如说处理int型对象。

例子1：

In [1]: print \'I am %d years old.\' % 25
I am 25 years old.

In [2]: print \'I am %s years old.\' % 25
I am 25 years old.

In [3]: print \'I am %r years old.\' % 25
I am 25 years old.

另外一些情况两者就不同了：
例子2：

In [4]: text = \' I am %d years old.\' % 25

In [5]: print \'I said: %s.\' % text
I said:  I am 25 years old..

In [6]: print \'I said: %r.\' % text
I said: \' I am 25 years old.\'.  #输出带了单引号。

例子3：

In [7]: import datetime

In [8]: d = datetime.date.today()

In [9]: print \'%s\' % d  
2017-02-17

In [10]: print \'%r\' % d
datetime.date(2017, 2, 17)

可见，%r打印时能够重现它所代表的对象(rper() unambiguously recreate the object it represents)

来自：http://blog.csdn.net/wusuopubupt/article/details/23678291