问删除未包含在axis中的空白索引列pandas标签[‘']

EN

for i in range(5,26):
    print(i)
    a = racimitos[racimitos['numeroLote']==i][['peso','fecha','numeroLote']]
    a.to_csv('racimitos{}.csv'.format(i), sep=',', header=True, index=True)

for i in range(5,26):
    print(i)
    a = racimitos[racimitos['numeroLote']==i][['peso','fecha','numeroLote']]
    a.to_csv('racimitos{}.csv'.format(i), sep=',', header=True, index=True)
    a.drop(columns=[' '], axis=1,)

KeyError                                  Traceback (most recent call last)
<ipython-input-18-e3ad718d5396> in <module>()
      9     a = racimitos[racimitos['numeroLote']==i][['peso','fecha','numeroLote']]
     10     a.to_csv('racimitos{}.csv'.format(i), sep=',', header=True, index=True)
---> 11     a.drop(columns=[' '], axis=1,)

~/anaconda3/envs/sioma/lib/python3.6/site-packages/pandas/core/indexes/base.py in drop(self, labels, errors)
   4385             if errors != 'ignore':
   4386                 raise KeyError(
-> 4387                     'labels %s not contained in axis' % labels[mask])
   4388             indexer = indexer[~mask]
   4389         return self.delete(indexer)

KeyError: "labels [' '] not contained in axis"