I want to put data consisting of a one-dimensional array into a two-dimensional array. I will assume that the number of rows and columns is 5. The code I tried is as follows.

data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
a = []
for i in range(5):
    a.append([])
    for j in range(5):
        a[i].append(j)
print(a)
# result : [[0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4]]
# I want this : [[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20]]

You don't have to worry about the last [20]. The important thing is that the row must change without duplicating the data. I want to solve it, but I can't think of any way. I ask for your help.

CodePudding user response：

This should deliever the desired output

data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
a = []
x_i = 5
x_j = 5

    for i in range(x_i):
        a.append([])
        for j in range(x_j):
            a[i].append(i*x_j j)
    print(a)

Output:

[[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20, 21, 22, 23, 24]]

CodePudding user response：

There are two issues with the current code.

1. It doesn't actually use any of the values from the variable data.
2. The data does not contain enough items to populate a 5x5 array.

After adding 0 to the beginning of the variable data and using the values from the variable, the code becomes

data = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
a = []
for i in range(5):
    a.append([])
    for j in range(5):
        if i*5 j >= len(data):
            break
        a[i].append(data[i*5 j])
print(a)

The output of the new code will be

[[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20]]

CodePudding user response：

By using list comprehension...

data = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

columns = 5
rows = 5
result = [data[i * columns: (i   1) * columns] for i in range(rows)]

print(result)
# [[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20]]

CodePudding user response：

You could use itertools.groupby with an integer division to create the groups

from itertools import groupby
data = [0, 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
grouped_data = [list(v) for k, v in groupby(data, key=lambda x: x//5)]
print(grouped_data)

Output

[[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20]]