how to sort an array function

Question

i have this code

pd.unique(df_dataset["City"])

then this output comes out

array(['Marseile', 'Barcelona', 'Valencia', 'Paris', 'Berlin', 'Lyon',
       'Seville', 'Palma', 'Munich', 'Hamburg', 'Madrid', 'Nice',
       'Granada'], dtype=object)

how do i add sort() function in the code

I have tried to run this

pd.unique(df_dataset["City"]).sorted("City", key=True)

but it doesn't seems correct

As I commented on @BENY's answer, sorting the whole column before taking the unique values is much less efficient than sorting after. Can you please test both on your data and give feedback? — mozway
– mozway, Commented Aug 1, 2021 at 4:49

BENY · Accepted Answer · 2021-08-01 02:17:21Z

3

Let us just with pandas

df_dataset["City"].sort_values().unique()

answered Aug 1, 2021 at 2:17

BENY

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1 Comment

mozway Over a year ago

It will be more expensive to sort first if there are many rows with duplicates, compared to a sort on unique values. You can test on something like pd.Series(np.random.choice(list('ABC'), 1000000)) to see for yourself (factor 10 in this case).

mozway · Accepted Answer · 2021-08-01 02:54:11Z

1

What about:

sorted(df_dataset["City"].unique())

If you want to keep the numpy.array type:

import numpy as np
np.sort(df_dataset["City"].unique())

edited Aug 1, 2021 at 2:54

answered Aug 1, 2021 at 1:46

mozway

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