pandas find closest value from other column to entire column
Question:
I have a pandas DataFrame with two columns of numbers:
index
X
Y
0
0.1
0.55
1
0.2
0.2
2
0.4
0.1
3
0.8
0.35
4
1
0.9
I want to find tuples of the indexes of the closest values.
For example for this dataframe I would want the result
(0,2), (1,1), (2,3), (3,4), (4,4)
I saw this link explaining how to do this for a given input, but I am wondering if there is a cleaner way to do this for my task.
Thanks in Advance!
Answers:
You can try list comprehension if you are not working with a huge dataset. Subtract (.sub()) each x value from each y value, get the absolute value (.abs()) and then get the int position of the smallest value in the Series (.argmin()).
l = [(idx, df['Y'].sub(x).abs().argmin()) for idx, x in enumerate(df['X'])]
# [(0, 2), (1, 1), (2, 3), (3, 4), (4, 4)]
Update – i.e., avoid the loop
l2 = list(zip(df.index, df['X'].sub([df['Y'].values]*len(df)).abs().agg(np.argmin)))
# [(0, 2), (1, 1), (2, 3), (3, 4), (4, 4)]
I have a pandas DataFrame with two columns of numbers:
| index | X | Y |
|---|---|---|
| 0 | 0.1 | 0.55 |
| 1 | 0.2 | 0.2 |
| 2 | 0.4 | 0.1 |
| 3 | 0.8 | 0.35 |
| 4 | 1 | 0.9 |
I want to find tuples of the indexes of the closest values.
For example for this dataframe I would want the result
(0,2), (1,1), (2,3), (3,4), (4,4)
I saw this link explaining how to do this for a given input, but I am wondering if there is a cleaner way to do this for my task.
Thanks in Advance!
You can try list comprehension if you are not working with a huge dataset. Subtract (.sub()) each x value from each y value, get the absolute value (.abs()) and then get the int position of the smallest value in the Series (.argmin()).
l = [(idx, df['Y'].sub(x).abs().argmin()) for idx, x in enumerate(df['X'])]
# [(0, 2), (1, 1), (2, 3), (3, 4), (4, 4)]
Update – i.e., avoid the loop
l2 = list(zip(df.index, df['X'].sub([df['Y'].values]*len(df)).abs().agg(np.argmin)))
# [(0, 2), (1, 1), (2, 3), (3, 4), (4, 4)]