作者 | zglgpython裡** | python與演算法社群
它優雅、簡潔，值得大家多多使用！今天盤點列表生成式在工作中的主要使用場景。
range快速生成連續列表
in [1]: a = range(11)
in [2]: a
out[2]: range(0, 11)
in [3]: list(a)
out[3]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
in [5]: a = range(0,11)
in [6]: b = [x**2 for x in a]
in [7]: b
out[7]: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
in [10]: a = range(11)
in [11]: c = [x**2 for x in a if x%2==0]
in [12]: c
out[12]: [0, 4, 16, 36, 64, 100]
in [13]: a = range(5)
in [14]: b = ['a','b','c','d','e']
in [20]: c = [str(y) + str(x) for x, y in zip(a,b)]
in [21]: c
out[21]: ['a0', 'b1', 'c2', 'd3', 'e4']
in [22]: a =
in [23]: b = [k+ '=' + v for k, v in a.items()]
in [24]: b = [k+ '=' + str(v) for k, v in a.items()]
in [25]: b
out[25]: ['a=1', 'b=2', 'c=3']
in [33]: [d for d in os.listdir('d:/summary')]
out[33]: ['a.txt.txt', 'python-100']
將值分組：
in [36]: def bifurcate(lst, filter):
...: return [
...: [x for i,x in enumerate(lst) if filter[i] == true],
...: [x for i,x in enumerate(lst) if filter[i] == false]
...: ]
...:
in [37]: bifurcate(['beep', 'boop', 'foo', 'bar'], [true, true, false, true])
out[37]: [['beep', 'boop', 'bar'], ['foo']]
in [38]: def bifurcate_by(lst, fn):
...: return [
...: [x for x in lst if fn(x)],
...: [x for x in lst if not fn(x)]
...: ]
...:
in [39]: bifurcate_by(['beep', 'boop', 'foo', 'bar'], lambda x: x[0] == 'b')
out[39]: [['beep', 'boop', 'bar'], ['foo']]
都把a, b用set 包裝
in [53]: def difference(a, b):
...: _a, _b =set(a),set(b)
...: return [item for item in _a if item not in _b]
...:
...:
in [54]: difference([1,1,2,3,3], [1, 2, 4])
out[54]: [3]
in [61]: def difference_by(a, b, fn):
...: ...: _b = set(map(fn, b))
...: ...: return [item for item in a if fn(item) not in _b]
...: ...:
...:
in [62]: from math import floor
...: difference_by([2.1, 1.2], [2.3, 3.4],floor)
out[62]: [1.2]
in [63]: difference_by([, ], , lambda v : v['x'])
out[63]:
in [64]: def filter_non_unique(lst):
...: return [item for item in lst if lst.count(item) == 1]
in [65]: filter_non_unique([1, 2, 2, 3, 4, 4, 5])
out[65]: [1, 3, 5]
Python列表生成式12個小功能，你常用哪幾個？
作者 zglg python與演算法社群 python裡表示乙個列表，對容器型別的資料進行運算和操作，生成新的列表最高效 快速的辦法，就是列表生成式。它優雅 簡潔，值得大家多多使用！今天盤點列表生成式在工作中的主要使用場景。range快速生成連續列表 in 1 a range 11 in 2 a o...
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