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- 扶我起来我还能敲 2017-09-24 03:08关注
小整数从-5到256 id相同指向同一位置(这个有可能跟系统或其他的设置有关,不过默认应该是这样的)
可以用is来判断两个变量是否id相同
可以用==来判断值是否相同如:In [1]: a = 256 In [2]: b = 256 In [3]: a is b Out[3]: True In [4]: a == b Out[4]: True In [5]: c = 257 In [6]: d = 257 In [7]: c is d Out[7]: False In [26]: c == d Out[26]: True # 负数 In [20]: a = -5 In [21]: b = -5 In [22]: a is b Out[22]: True In [23]: a = -6 In [24]: b = -6 In [25]: a is b Out[25]: False # 变量赋值 In [27]: c = 257 In [28]: d = c In [29]: c is d Out[29]: True # 字符串 In [30]: a = 'str' In [31]: b = 'str' In [32]: a is b Out[32]: True # 带空格的字符串 In [36]: a = 'hello world' In [37]: b = 'hello world' In [38]: a is b Out[38]: False
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