How to find closest elements to each other in two dataframes?

Question

Given two dataframes:

df_1:

c1, c2
a, 0
b, 0
c, 2

df_2:

c3, c4
d, 2
e, 3
f, 7

How would you find the closest c2 row to the closest c4 row, and create a new dataframe which has these in corresponding rows next to each other?

Example output:

a, d (zero is closest to two)
b, d (second entry of zero counts as being closest to two)
c, d (this is the closest)

Answer 1

You could start by creating a new dataFrame which is a copy of your original dataframe containing c1, c2 .

Then by using an apply function on the c2 column, you can use the following command to find the closest value and assign it to another column.

result_index = df['col_to_search'].sub(search_value).abs().idxmin()