DataFrame.
applymap
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar to every element of a DataFrame.
Python function, returns a single value from a single value.
Transformed DataFrame.
See also
DataFrame.apply
Apply a function along input axis of DataFrame.
Notes
In the current implementation applymap calls func twice on the first column/row to decide whether it can take a fast or slow code path. This can lead to unexpected behavior if func has side-effects, as they will take effect twice for the first column/row.
Examples
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]]) >>> df 0 1 0 1.000 2.120 1 3.356 4.567
>>> df.applymap(lambda x: len(str(x))) 0 1 0 3 4 1 5 5
Note that a vectorized version of func often exists, which will be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2) 0 1 0 1.000000 4.494400 1 11.262736 20.857489
But it’s better to avoid applymap in that case.
>>> df ** 2 0 1 0 1.000000 4.494400 1 11.262736 20.857489