Right way to reverse a pandas DataFrame?

Question

Here is my code: ``` import pandas as pd data = pd.DataFrame({'Odd':[1,3,5,6,7,9], 'Even':[0,2,4,6,8,10]}) for i in reversed(data): print(data['Odd'], data['Even']) ``` When I run this code, i get the following error: ``` Traceback (most recent call last): File "C:\Python33\lib\site-packages\pandas\core\generic.py", line 665, in _get_item_cache return cache[item] KeyError: 5 During handling of the above exception, another exception occurred: Traceback (most recent call last): File "C:\Users\*****\Documents\******\********\****.py", line 5, in <module> for i in reversed(data): File "C:\Python33\lib\site-packages\pandas\core\frame.py", line 2003, in __getitem__ return self._get_item_cache(key) File "C:\Python33\lib\site-packages\pandas\core\generic.py", line 667, in _get_item_cache values = self._data.get(item) File "C:\Python33\lib\site-packages\pandas\core\internals.py", line 1656, in get _, block = self._find_block(item) File "C:\Python33\lib\site-packages\pandas\core\internals.py",…

Accepted Answer

```
data.reindex(index=data.index[::-1])
```

or simply:

```
data.iloc[::-1]
```

will reverse your data frame, if you want to have a `for` loop which goes from down to up you may do:

```
for idx in reversed(data.index):
    print(idx, data.loc[idx, 'Even'], data.loc[idx, 'Odd'])
```

or

```
for idx in reversed(data.index):
    print(idx, data.Even[idx], data.Odd[idx])
```

You are getting an error because `reversed` first calls `data.__len__()` which returns 6. Then it tries to call `data[j - 1]` for `j` in `range(6, 0, -1)`, and the first call would be `data[5]`; but in pandas dataframe `data[5]` means column 5, and there is no column 5 so it will throw an exception. ( see docs )

Right way to reverse a pandas DataFrame?

Solution

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