按行对列表列表进行垂直排序

Question

very new to coding, want to compare the same indices within the list of lists in order to align the numbers vertically so they are in numerical order:

Write a function called sort_by_direction that takes two parameters. The first parameter called seq will be a list of lists where the number of lists is equal to the number of items in each list. The second parameter called direc will give the direction to sort each list of lists. direc will have four possible values, "L" which will sort each row in ascending order, "R" which will sort each row in descending order, "U" which sorts each column in ascending order, and "D" which sorts each column in descending order.

example = [[3, 6, 1], [5, 2, 2], [0, 8, 7]]
sort_by_direction(example, 'L') # should return [[1, 3, 6], [2, 2, 5], [0, 7, 8]]

example = [[3, 6, 1], [5, 2, 2], [0, 8, 7]]
sort_by_direction(example, 'R') # should return [[6, 3, 1], [5, 2, 2], [8, 7, 0]]

example = [[3, 6, 1], [5, 2, 2], [0, 8, 7]]
sort_by_direction(example, 'U') # should return [[5, 8, 7], [3, 6, 2], [0, 2, 1]]

[[5, 8, 7],

 [3, 6, 2],

 [0, 2, 1]]

example = [[3, 6, 1], [5, 2, 2], [0, 8, 7]]
sort_by_direction(example, 'D') # should return [[0, 2, 1], [3, 6, 2], [5, 8, 7]]

[[0, 2, 1],

 [3, 6, 2],

 [5, 8, 7]]

def sort_by_direction(seq,direc):
    new = []
    if direc == 'L':
        for lst in seq:
            lst.sort()
            new.append(lst)
    elif direc == 'R':
        for lst in seq:
            lst.sort()
            lst.reverse()
            new.append(lst)
    elif direc == 'U':
        for lst in seq:
            for idx, num in enumerate(zip(lst)):
            ????

Answer 1

Sorting every row is simple.

Ascending:

[sorted(x) for x in example]

Descending:

[sorted(x, reverse = True) for x in example]

To sort column-wise, you could transpose the nested list first, then sort the same way as shown above, then transpose back. An easy way to transpose a list of lists:

transposed = list(zip(*example))

Then, sort it and transpose back:

tmp = [sorted(x, reverse = True) for x in transposed]
result = list(zip(*tmp))

And of course it was already in "The Simpsons" NumPy:

import numpy
example = numpy.array([[3, 6, 1], [5, 2, 2], [0, 8, 7]])
result = numpy.sort(example, axis = 0) # only use axis = 0 to sort vertically
# add this to reverse the order:
result = numpy.flip(result, axis = 0) # only use axis = 0 if sorted vertically

Answer 2

You can use pandas for that:

def sort_by_direction(seq,direc):
    new = []
    if direc == 'L':
        for lst in seq:
            lst.sort()
            new.append(lst)
    elif direc == 'R':
        for lst in seq:
            lst.sort()
            lst.reverse()
            new.append(lst)
    elif direc == 'U':
         df = pd.DataFrame(data=seq)
         k = df.apply(lambda x: (x.sort_values(ascending=False)).to_list(),axis=0)
         return k.values
    
    elif direc == 'D':
         df = pd.DataFrame(data=seq)
         k = df.apply(lambda x: (x.sort_values(ascending=True)).to_list(),axis=0)
         return k.values
        
example = [[3, 6, 1], [5, 2, 2], [0, 8, 7]]
sort_by_direction(example, 'D') 

Result:

array([[0, 2, 1],
       [3, 6, 2],
       [5, 8, 7]])