Choice of sorting algorithm. See also numpy.sort() for more information. mergesort and stable are the only stable algorithms. For DataFrames, this option is only applied when sorting on a single column or label.
na_position: {‘first’, ‘last’}, default ‘last’
Puts NaNs at the beginning if first; last puts NaNs at the end.
ignore_index: bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
key: callable, optional
Apply the key function to the values before sorting. This is similar to the key argument in the builtin sorted() function, with the notable difference that this key function should be vectorized. It should expect a Series and return a Series with the same shape as the input. It will be applied to each column in by independently. The values in the returned Series will be used as the keys for sorting.
Returns:
DataFrame or None
DataFrame with sorted values or None if inplace=True.
See also:
DataFrame.sort_index
Sort a DataFrame by the index.
Series.sort_values
Similar method for a Series.
Examples:
>>> df = pd.DataFrame(... {... "col1": ["A", "A", "B", np.nan, "D", "C"],... "col2": [2, 1, 9, 8, 7, 4],... "col3": [0, 1, 9, 4, 2, 3],... "col4": ["a", "B", "c", "D", "e", "F"],... }... )>>> df col1 col2 col3 col40 A 2 0 a1 A 1 1 B2 B 9 9 c3 NaN 8 4 D4 D 7 2 e5 C 4 3 F
Sort by a single column
In this case, we are sorting the rows according to values in col1:
>>> df.sort_values(by=["col1"]) col1 col2 col3 col40 A 2 0 a1 A 1 1 B2 B 9 9 c5 C 4 3 F4 D 7 2 e3 NaN 8 4 D
Sort by multiple columns
You can also provide multiple columns to by argument, as shown below. In this example, the rows are first sorted according to col1, and then the rows that have an identical value in col1 are sorted according to col2.
>>> df.sort_values(by=["col1", "col2"]) col1 col2 col3 col41 A 1 1 B0 A 2 0 a2 B 9 9 c5 C 4 3 F4 D 7 2 e3 NaN 8 4 D
Sort in a descending order
The sort order can be reversed using ascending argument, as shown below:
>>> df.sort_values(by="col1", ascending=False) col1 col2 col3 col44 D 7 2 e5 C 4 3 F2 B 9 9 c0 A 2 0 a1 A 1 1 B3 NaN 8 4 D
Placing anyNAfirst
Note that in the above example, the rows that contain an NA value in their col1 are placed at the end of the dataframe. This behavior can be modified via na_position argument, as shown below:
>>> df.sort_values(by="col1", ascending=False, na_position="first") col1 col2 col3 col43 NaN 8 4 D4 D 7 2 e5 C 4 3 F2 B 9 9 c0 A 2 0 a1 A 1 1 B
Customized sort order
The key argument allows for a further customization of sorting behaviour. For example, you may want to ignore the letter’s case when sorting strings:
>>> df.sort_values(by="col4", key=lambda col: col.str.lower()) col1 col2 col3 col40 A 2 0 a1 A 1 1 B2 B 9 9 c3 NaN 8 4 D4 D 7 2 e5 C 4 3 F
Another typical example is natural sorting. This can be done using natsort package, which provides a function to generate a key to sort data in their natural order: