[FIXED] Vectorized Lookup in Dataframe Using Numpy Array

Issue

Given a numpy array such as the one below, is it possible to use vectorization to return the associated value in column HHt without using a for loop?

ex_arr = [2643, 2644, 2647]

for i in ex_arr:

    h_p = df.at[i, "HHt"]

Example df:

	HHt
2643	1
2644	2
2645	3
2646	4
2647	5
2648	6
2649	7
2650	8

Expected result: 1 2 5

Solution

Use DataFrame.loc, if need list or array add Series.to_list or Series.to_numpy:

print (df.loc[ex_arr,'HHt'].to_list())
[1, 2, 5]

print (df.loc[ex_arr,'HHt'].to_numpy())
[1 2 5]

Answered By - jezrael