(编辑:jimmy 日期: 2024/11/17 浏览:2)
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 >
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