浅谈python中set使用

In [2]: a = set()  # 常用操作1  In [3]: a Out[3]: set()  In [4]: type(a) Out[4]: set In [5]: b = set([1, 3])  In [6]: b Out[6]: {1, 3}  In [7]: type(b) Out[7]: set In [8]: b.update(2) ---------------------------------------------------------------------------TypeError                 Traceback (most recent call last) <ipython-input-8-d51e2fe4c50a> in <module>() ----> 1 b.update(2)  TypeError: 'int' object is not iterable  In [9]: b.update({2})  In [10]: b Out[10]: {1, 2, 3}  In [11]: b.update([4])  In [12]: b Out[12]: {1, 2, 3, 4}  In [13]: a.di a.difference     a.difference_update a.discard  In [13]: a.dif a.difference     a.difference_update  In [13]: a.difference(b) Out[13]: set()  In [14]: a Out[14]: set()  In [15]: b.difference(a) Out[15]: {1, 2, 3, 4}  In [16]:

In [16]: a.add({1, 3}) ---------------------------------------------------------------------------TypeError                 Traceback (most recent call last) <ipython-input-16-98cdf4d0875e> in <module>() ----> 1 a.add({1, 3})  TypeError: unhashable type: 'set' In [17]: a.add(4)  In [18]: a Out[18]: {4}  In [19]: a.issu a.issubset  a.issuperset  In [19]: a.issubset(b) Out[19]: True In [20]: a.remove(4)  In [21]: a Out[21]: set()  In [22]: a.union(b) Out[22]: {1, 2, 3, 4}  In [23]: a Out[23]: set()  In [24]: b Out[24]: {1, 2, 3, 4}  In [25]: b.pop() Out[25]: 1 In [26]: a.copy(b) ---------------------------------------------------------------------------TypeError                 Traceback (most recent call last) <ipython-input-26-9e8a5f057ffd> in <module>() ----> 1 a.copy(b)  TypeError: copy() takes no arguments (1 given)  In [27]: a.copy() Out[27]: set()  In [28]: c = a.copy()  In [29]: c Out[29]: set()  In [30]: a Out[30]: set()  In [31]: a.add({234}) ---------------------------------------------------------------------------TypeError                 Traceback (most recent call last) <ipython-input-31-6073e02d68a9> in <module>() ----> 1 a.add({234})  TypeError: unhashable type: 'set' In [32]: a.add(234)  In [33]: c Out[33]: set()  In [34]: a Out[34]: {234}

In [35]: a.clear()  In [36]: a Out[36]: set()  In [39]: a = {1}  In [40]: b = {1, 2}  In [41]: a.intersection(b) Out[41]: {1}  In [43]: a Out[43]: {1}  In [44]: b = {1, 2, 3}  In [45]: a.union(b) Out[45]: {1, 2, 3}  In [45]: a.union(b) Out[45]: {1, 2, 3}  In [46]: a & b Out[46]: {1}  In [47]: a ^ b Out[47]: {2, 3}  In [48]: a - b Out[48]: set()  In [49]: b - a Out[49]: {2, 3}<BR><BR> ?1234567891011 In [50]: a > b Out[50]: False In [51]: b > a Out[51]: True In [52]: a == b Out[52]: False In [53]: a != b Out[53]: True