如何将嵌套列表转换成字典

Question

I am supposed to convert a nested list into a dictionary. If I have the list:

data=[[['1','2','-2'], ['3','-1','4']]

I want it to become:

d={(0, 0): 1, (0, 1): 3, (1, 0): 2, (1, 1): -1, (2, 0): -2, (2, 1): 4}

The tricky part is I you need to see this list as a matrix:

'1','2','-2'
'3','-1','4'

• Note:Keys in d are not those values' position in that list. keys should be positions of values in that matrix. For example, the key of '3' is (0,1) while the position of '3' in the list is [1][0]. (0,1) should be column o and row 1 in that matrix(I understand it in this way)

So the keys in the dictionary should be their position in that matrix. I am confused and I tried:

for m in range(len(data)):
    for n in range(len(data[m])):
        d[(m,n)]= data[n][m]

I know it's wrong because it will become out of range. I am so struggling with it.

Answer 1

像这样的东西：

data_field = {(i,j): item  for i, lst in enumerate(data) for j,item in enumerate(lst)}

Answer 2

Your current data is invalid syntax, however, I believe this is what you are looking for:

data= [['1','2','-2'], ['3','-1','4']]
new_result = {(a, i):data[i][a] for i in range(len(data)) for a in range(len(data[0]))}

Output:

{(0, 1): '3', (0, 0): '1', (2, 1): '4', (2, 0): '-2', (1, 0): '2', (1, 1): '-1'}

Answer 3

I believe your list of lists already represents what you want, just a bit inverted. You say you want to do matrix[(2,1)] to get 4 . Is it really so hard to do data[1][2] instead? But since you regard the inversion as indispensable, you can convert the list of lists this way.

>>> data=[['1','2','-2'], ['3','-1','4']]  # I corrected your mismatched parens
>>> matrix={}
>>> for x, a in enumerate(zip(*data)):
        for y, b in enumerate(a):
            matrix[(x,y)] = int(b)
>>> matrix
{(0, 0): 1, (0, 1): 3, (1, 0): 2, (1, 1): -1, (2, 0): -2, (2, 1): 4}
>>> matrix[(2,1)]
4

A more readable way to do this would be to write a function to do the inversion, instead of reorganizing the data:

>>> def matrix(coords):
        y, x = coords
        return int (data[x][y])
>>> matrix((2,1))
4 

Answer 4

I personally think that long comprehensions look unintuitive, so:

for y, rows in enumerate(data):
    for x, col in enumerate(rows):
        d[(x,y)] = col