python 3嵌套理解

Question

是否有一种智能列表/字典理解方式来获得下面的预期输出:

import numpy as np
freq_mat = np.random.randint(2,size=(4,5));
tokens = ['a', 'b', 'c', 'd', 'e'];
labels = ['X', 'S', 'Y', 'S'];

freq_mat 的预期输出

array([[1, 0, 0, 1, 1],
       [0, 0, 0, 0, 1],
       [1, 0, 1, 1, 0],
       [0, 1, 0, 0, 0]])

应该喜欢以下内容:

[({'a': True, 'b': False, 'c': False, 'd': True, 'e': True}, 'X'),
 ({'a': False, 'b': False, 'c': False, 'd': False, 'e': True}, 'S'),
 ({'a': True, 'b': False, 'c': True, 'd': True, 'e': False}, 'Y'),
 ({'a': False, 'b': True, 'c': False, 'd': False, 'e': False}, 'S')]

Answer 1

您可以将该代码折叠为:

代码:

featureset = [
    ({key: val > 0 for val in row for key in tokens}, label)
    for row, label in zip(freq_mat, labels)]

测试代码:

freq_mat = np.random.randint(2, size=(4, 5));
tokens = ['a', 'b', 'c', 'd', 'e'];
labels = ['X', 'S', 'Y', 'S'];

featureset2 = []
for row, label in zip(freq_mat, labels):
    d = dict()
    for key in tokens:
        for val in row:
            d[key] = val > 0
    featureset2.append((d, label))

featureset = [
    ({key: val > 0 for val in row for key in tokens}, label)
    for row, label in zip(freq_mat, labels)]

assert featureset == featureset2