生成有序 XY 坐标

Question

I'm writetwo python dataframe columns so that two coordinates, X and Y, will increment down their respective columns. For example:

|  X  |  Y  |
|:----|----:|
|  0  |  0  |
|  0  |  1  |
|  0  |  2  |
|  0  |  3  |
|  0  |  4  |
|  1  |  0  |
|  1  |  1  |
|  1  |  2  |
|  1  |  3  |
|  1  |  4  |
|  2  |  0  |
|  2  |  1  |
|  2  |  2  |
|  2  |  3  |
|  2  |  4  |
| ... | ... |

Any ideas how to generate these columns?

Answer 1

You can generate dictionary with iteration and then create DataFrame from that you can check below sample for that;

import pandas as pd

my_df = []
for i in range(0,10):
    d = {
        'x' : i,  # some formula for obtaining values
        'y' : i*2,

    }
    my_df.append(d)

my_df = pd.DataFrame(my_df)
print(my_df)

To generate values you require you need to fiddle with iteration. Leaving up to you:). Logic would be this, you need to add (0,1,2,3,4) values to y column, so you can get modulo each iteration and add accordingly. For x column you need to +1 to x value after each 4th iteration.

Answer 2

Just use range() and a list comprehension (modify the 3 if you want another length):

df = pd.DataFrame(
    [[n, m] for n in range(3) for m in range(5)],
    columns=["X", "Y"]
)

Result:

    X  Y
0   0  0
1   0  1
2   0  2
3   0  3
4   0  4
5   1  0
6   1  1
7   1  2
8   1  3
9   1  4
10  2  0
11  2  1
12  2  2
13  2  3
14  2  4

Or use itertools.product to get the same result:

from itertools import product

df = pd.DataFrame(product(range(3), range(5)), columns=["X", "Y"])