ENH: Why pandas does not offer (yet) the possibility of rotating a dataframe ? #52305
Description
Feature Type
-
Adding new functionality to pandas
-
Changing existing functionality in pandas
-
Removing existing functionality in pandas
Problem Description
One day while doing some routine stuff with pandas, I was chaining a couple of methods to transform a DataFrame. However, I ended up with dozens of columns, all of which were shifted by one column to the right. I run through the API but I couldn't find a method to rotate the columns to the specific positions I was expecting, and my only options seemed to be either using set_axis, reindex or even slicing [[col1, col2, ..]] as a last chain. TBH, manually writing dozens of columns would not have been a good idea! While that day I was only concerned with rotating the columns, I later found myself in situations where I also needed to rotate the index. This led me to open this issue and suggest adding a rotate method to ./pandas/core/frame.py in the future, but I wonder if it's possible and/or worthwhile.
Feature Description
The rotate would look like something like this :
import pandas as pd
import numpy as np
#for reproducibility
class TwinDataFrame(pd.DataFrame):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
def rotate(self, wheels: int, clockwise: bool = True, axis: int = 1) -> pd.DataFrame:
if axis == 1:
len_axis = len(self.columns)
axis_names = self.columns
elif axis == 0:
len_axis = len(self)
axis_names = self.index
if wheels % len_axis == 0:
return self
shift = wheels % len_axis if clockwise else -wheels % len_axis
result = self.reindex(axis_names[np.roll(np.arange(len_axis), shift)], axis=axis)
return result
Test & Output :
df = TwinDataFrame({"A": [1, 2, 3, 4],
"B": [5, 6, 7, 8],
"C": [9, 10, 11, 12]})
print(df)
A B C
0 1 5 9
1 2 6 10
2 3 7 11
3 4 8 12
rot_df = df.rotate(wheels=2, clockwise=False, axis=1)
print(rot_df)
C A B
0 9 1 5
1 10 2 6
2 11 3 7
3 12 4 8
Additional Context
No response