python中set常用操作汇总_Python

sets 支持 x in set, len(set),和 for x in set。作为一个无序的集合，sets不记录元素位置或者插入点。因此，sets不支持 indexing, slicing, 或其它类序列（sequence-like）的操作。

下面我们通过几个例子，来简单说明下

常用操作1

									In [2]: a = set() 

									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]:

常用操作2

									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}

常用操作3

									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}

									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

python中set常用操作汇总

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