Hello. I have an inquiry about changing the value of Pandas. KeyError

csv = pd.read_csv("bmi.csv")

csv.head()

I made the data frame as below by making the code as above

   height       weight      label

0       195     64      thin

1   165         58      normal

2   130         37      normal

3   137         53      fat

4   120     40      fat

I wanted to change the height and weight values here, so I made the following code.

csv["height"] = csv["height"]/200
csv["weight"] = csv["weight"]/100
print(csv["weight"])
bclass = {"thin": [1, 0, 0], "normal" : [0, 1, 0], "fat" : [0, 0, 1]}
csv["label_pat"] = csv["label"].apply(lambda x : np.array(bclass[x]))

Since then, it has not been processed due to the following error, but is there anyone who knows?

KeyError                                  Traceback (most recent call last)
~\Anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2656             try:
-> 2657                 return self._engine.get_loc(key)
   2658             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: 'weight'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-9-9d3d4ac66f19> in <module>
      1 csv["height"] = csv["height"]/200
----> 2 csv["weight"] = csv["weight"]/100
      3 print(csv["weight"])
      4 bclass = {"thin": [1, 0, 0], "normal" : [0, 1, 0], "fat" : [0, 0, 1]}
      5 csv["label_pat"] = csv["label"].apply(lambda x : np.array(bclass[x]))

~\Anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2925             if self.columns.nlevels > 1:
   2926                 return self._getitem_multilevel(key)
-> 2927             indexer = self.columns.get_loc(key)
   2928             if is_integer(indexer):
   2929                 indexer = [indexer]

~\Anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2657                 return self._engine.get_loc(key)
   2658             except KeyError:
-> 2659                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2660         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2661         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: 'weight'

I can't because of the weight value. What is it? Masters, please tell us the answer.

python keyerror

2022-09-21 19:17

1 Answers

KeyError is from csv['weight']. If you only look at the error message, csv means that you cannot access the key 'weight' in the data frame, and that error occurs when there is no column named 'weight'.

However, when I marked the data frame with .head(), it looked like there was a column named weight. You might want to make sure that both sides of the column name contain no blanks or printable characters.

print(csv.columns)

When you do, the column names are displayed with quotes. Check if there are any blanks.

For more clarity, see

print('weight' in csv.clumns)

Check to see if True appears.

2022-09-21 19:17

If you have any answers or tips

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