While slicing the pivotted data frame unable to get the column names and throwing error below.Unable to find out what is happening as though columns available it is not extracted during slicing the dataframe. Data set is 'MovieLens 100K Dataset'
Data set is
movieRatings=ratings.pivot_table(index=['user_id'],columns=['title'],values=['rating'])
Out of 'movieRatings.head()' as below
rating
title 'Til There Was You (1997) 1-900 (1994) 101 Dalmatians (1996) 12 Angry Men (1957) 187 (1997) 2 Days in the Valley (1996) 20,000 Leagues Under the Sea (1954) 2001: A Space Odyssey (1968) 3 Ninjas: High Noon At Mega Mountain (1998) 39 Steps, The (1935) ... Yankee Zulu (1994) Year of the Horse (1997) You So Crazy (1994) Young Frankenstein (1974) Young Guns (1988) Young Guns II (1990) Young Poisoner's Handbook, The (1995) Zeus and Roxanne (1997) unknown Á köldum klaka (Cold Fever) (1994)
user_id
1 NaN NaN 2.0 5.0 NaN NaN 3.0 4.0 NaN NaN ... NaN NaN NaN 5.0 3.0 NaN NaN NaN 4.0 NaN
2 NaN NaN NaN NaN NaN NaN NaN NaN 1.0 NaN ... NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
3 NaN NaN NaN NaN 2.0 NaN NaN NaN NaN NaN ... NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
4 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN ... NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
5 NaN NaN 2.0 NaN NaN NaN NaN 4.0 NaN NaN ... NaN NaN NaN 4.0 NaN NaN NaN NaN 4.0 NaN
Next statement
starWarsRatings = movieRatings["12 Angry Men (1957)"]
starWarsRatings.head()
Error message
KeyError Traceback (most recent call last)
D:\Anaconda\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
2645 try:
-> 2646 return self._engine.get_loc(key)
2647 except KeyError:
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
KeyError: '12 Angry Men (1957)'
During handling of the above exception, another exception occurred:
KeyError Traceback (most recent call last)
<ipython-input-134-9c0f30e1dc98> in <module>
----> 1 starWarsRatings = movieRatings["12 Angry Men (1957)"]
2 starWarsRatings.head()
D:\Anaconda\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
2797 if is_single_key:
2798 if self.columns.nlevels > 1:
-> 2799 return self._getitem_multilevel(key)
2800 indexer = self.columns.get_loc(key)
2801 if is_integer(indexer):
D:\Anaconda\lib\site-packages\pandas\core\frame.py in _getitem_multilevel(self, key)
2847 def _getitem_multilevel(self, key):
2848 # self.columns is a MultiIndex
-> 2849 loc = self.columns.get_loc(key)
2850 if isinstance(loc, (slice, Series, np.ndarray, Index)):
2851 new_columns = self.columns[loc]
D:\Anaconda\lib\site-packages\pandas\core\indexes\multi.py in get_loc(self, key, method)
2660 if not isinstance(key, (tuple, list)):
2661 # not including list here breaks some indexing, xref #30892
-> 2662 loc = self._get_level_indexer(key, level=0)
2663 return _maybe_to_slice(loc)
2664
D:\Anaconda\lib\site-packages\pandas\core\indexes\multi.py in _get_level_indexer(self, key, level, indexer)
2927 else:
2928
-> 2929 code = self._get_loc_single_level_index(level_index, key)
2930
2931 if level > 0 or self.lexsort_depth == 0:
D:\Anaconda\lib\site-packages\pandas\core\indexes\multi.py in _get_loc_single_level_index(self, level_index, key)
2596 return -1
2597 else:
-> 2598 return level_index.get_loc(key)
2599
2600 def get_loc(self, key, method=None):
D:\Anaconda\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
2646 return self._engine.get_loc(key)
2647 except KeyError:
-> 2648 return self._engine.get_loc(self._maybe_cast_indexer(key))
2649 indexer = self.get_indexer([key], method=method, tolerance=tolerance)
2650 if indexer.ndim > 1 or indexer.size > 1:
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()
KeyError: '12 Angry Men (1957)'
Edited - Original answer wasn't what the OP wanted.
The problem is with the way you created it. An array/list values argument is interpreted differently than a simple string. In this case, you need to just use the string one. If you use the array, you'll need to index with [ratings, ...].
So just change the declaration of the table and it should work.
table = df.pivot_table(index=[..], values='JUST A STRING', columns=[..])