基于列表理解和条件的元素比较

Question

我有两份表格：

a = [[x1, 1], [x2, 0], [x3, 4], [x4, 12], [x5, 15]]

b = [[x2, 10], [x3, 41], [x7, 50]]

我想我可以在下面这样做，得到ids x1，x2，x3等等。

x = [item for item in b if item in a]

print(x)
[[x2, 10], [x3, 41]]

实际上，我想打印a中b中的元素，并比较它们的值。

[x2, 10] -> [x2, 0]
[x3, 41] -> [x3, 4]

因此，在上面的示例中，只打印if b[0][1] == 0 & a[1][1] != 0中的元素。

任何帮助都将不胜感激！

Answer 1

您可以使用：

a = [['x1', 1], ['x2', 0], ['x3', 4], ['x4', 12], ['x5', 15]]

b = [['x2', 10], ['x3', 41], ['x7', 50]]

a_dict = dict(a)

print('    b           a')
for x, val in b:
    if x in a_dict:
        print(f'[{x}, {val}] --> [{x}, {a_dict[x]}]')

产出：

    b           a
[x2, 10] --> [x2, 0]
[x3, 41] --> [x3, 4]

Answer 2

像这样的东西可能就是你想要的：

ax = [item[0] for item in a]
x = [item for item in b if item[0] in ax]
print x

Answer 3

list comprehension与enumerate的结合

Ex.

a = [['x1', 1], ['x2', 0], ['x3', 4], ['x4', 12], ['x5', 15]]
b = [['x2', 10], ['x3', 41], ['x7', 50]]
x = [a[index] for y in b for index,x in enumerate(a) if y[0] == x[0]]
print(x)

O/P:

[['x2', 0], ['x3', 4]]