Pandas unstack problems: ValueError: Index contains duplicate entries, cannot reshape is an error which usually happens when your DataFrame has duplicate values with the same index.
In this article I am going to explain what happens when you get this error and how you can solve it with a main solution, we will also explore other solutions which can possibly solve the issue.
Exploring Pandas unstack problems ValueError: Index contains duplicate entries, cannot reshape
The error usually happens when your DataFrame has duplicate values with the same index.
The message of the error should look like this, there are a lot of errors out there and you do not want to confuse the errors.
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ValueError Traceback (most recent call last)
<ipython-input-39-bc1e237a0ed7> in <module>()
----> 1 e.unstack('location')
C:\Anaconda\envs\sandbox\lib\site-packages\pandas\core\reshape.pyc in _make_selectors(self)
144 if mask.sum() < len(self.index):
145 raise ValueError('Index contains duplicate entries, '
146 'cannot reshape')
ValueError: Index contains duplicate entries, cannot reshape
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To solve the problem above, I have 2 options which have worked for me, bellow is a detailed explanation of both.
Solution : Two simple options.
The problem is that DataFrame has duplicate values with the same index.
The easiest solution is to get back to df after reset_index and use pivot_table. Just like in the line bellow.
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df1.reset_index().pivot_table(values=4, index=[0, 1, 2], columns=3, aggfunc='mean')
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The fixe above should be enough to understand and handle the error, try the last option if this one did not do the trick.
The second option is to retain the default index column row # and set the index using the names of the columns you have.
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e.set_index(['id', 'age', 'gender'], append=True)
#'id', 'age', 'gender' are our columns
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I hope this guide solved your problem, thank you for reading.
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Summing-up
Finally, we are at the end of this article, I hope this article has been helpful, I hope you solved your problem, coding can be hard when you have a lot of confusing errors here and there.
Thank you for reading, keep learning and keep coding, cheers. If you want to learn more about Python, please check out the Python Documentation : https://docs.python.org/3/