宜配屋

python消除序列的重复值并保持顺序不变的实例

yipeiwu_com7年前 (2020-03-06)Python基础

python 消除序列的重复值，并保持原来顺序

1、如果仅仅消除重复元素，可以简单的构造一个集合

$ python
Python 3.5.2 (default, Nov 23 2017, 16:37:01) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = [1 , 3, 5, 1, 8, 1, 5]
>>> set(a)
{8, 1, 3, 5}
>>>

2、利用集合或者生成器解决：值必须是hashable类型

$ python
Python 3.5.2 (default, Nov 23 2017, 16:37:01) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> def dupe(items):
... seen = set()
... for item in items:
... if item not in seen:
... yield item
... seen.add(item)
... 
>>> a = [1 , 3, 5, 1, 8, 1, 5]
>>> list(dupe(a))
[1, 3, 5, 8]
>>>

3、消除元素不可哈希：如字典类型

Python 3.5.2 (default, Nov 23 2017, 16:37:01) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> def rem(items, key=None):
... seen = set()
... for item in items:
... va = item if key is None else key(item)
... if va not in seen:
... yield item
... seen.add(va)
... 
>>> a = [ {'x':1, 'y':2}, {'x':1, 'y':3}, {'x':1, 'y':2}, {'x':2, 'y':4}]>>> list(rem(a, key=lambda d: (d['x'],d['y'])))
[{'y': 2, 'x': 1}, {'y': 3, 'x': 1}, {'y': 4, 'x': 2}]
>>> list(rem(a, key=lambda d: d['x']))
[{'y': 2, 'x': 1}, {'y': 4, 'x': 2}]

>>>>>> #lambda is an anonymous function:
... fuc = lambda : 'haha'
>>> print (f())
>>> print (fuc())
haha
>>>

以上这篇python消除序列的重复值并保持顺序不变的实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持【听图阁-专注于Python设计】。