nsmallest(self, n: 'int', columns: 'IndexLabel', keep: 'str' = 'first') -> 'DataFrame'
Return the first n rows with the smallest values in :None:None:`columns`, in ascending order. The columns that are not specified are returned as well, but not used for ordering.
This method is equivalent to df.sort_values(columns, ascending=True).head(n)
, but more performant.
Number of items to retrieve.
Column name or names to order by.
Where there are duplicate values:
Return the first n rows ordered by :None:None:`columns` in ascending order.
DataFrame.head
Return the first :None:None:`n` rows without re-ordering.
DataFrame.nlargest
Return the first :None:None:`n` rows ordered by :None:None:`columns` in descending order.
DataFrame.sort_values
Sort DataFrame by the values.
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 337000,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
... df population GDP alpha-2 Italy 59000000 1937894 IT France 65000000 2583560 FR Malta 434000 12011 MT Maldives 434000 4520 MV Brunei 434000 12128 BN Iceland 337000 17036 IS Nauru 337000 182 NR Tuvalu 11300 38 TV Anguilla 11300 311 AI
In the following example, we will use nsmallest
to select the three rows having the smallest values in column "population".
>>> df.nsmallest(3, 'population') population GDP alpha-2 Tuvalu 11300 38 TV Anguilla 11300 311 AI Iceland 337000 17036 IS
When using keep='last'
, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last') population GDP alpha-2 Anguilla 11300 311 AI Tuvalu 11300 38 TV Nauru 337000 182 NR
When using keep='all'
, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all') population GDP alpha-2 Tuvalu 11300 38 TV Anguilla 11300 311 AI Iceland 337000 17036 IS Nauru 337000 182 NR
To order by the smallest values in column "population" and then "GDP", we can specify multiple columns like in the next example.
This example is valid syntax, but we were not able to check execution>>> df.nsmallest(3, ['population', 'GDP']) population GDP alpha-2 Tuvalu 11300 38 TV Anguilla 11300 311 AI Nauru 337000 182 NRSee :
The following pages refer to to this document either explicitly or contain code examples using this.
pandas.core.frame.DataFrame.nlargest
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