在熊猫数据框中查找重复项时出现不可散列列表错误

Question

您好，这真的让我很困惑，因为我在大型数据框上使用了一个命令：

df.duplicated(subset=None, keep='first)

这看起来与文档所说的相同：

DataFrame.duplicated(subset=None, keep='first')

我只是使用 df，但是，我得到的只是以下回溯：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-53-529f7b7a97fb> in <module>()
----> 1 df.duplicated(subset=None, keep='first')

/anaconda3/lib/python3.7/site-packages/pandas/core/frame.py in duplicated(self, subset, keep)
   4383         vals = (col.values for name, col in self.iteritems()
   4384                 if name in subset)
-> 4385         labels, shape = map(list, zip(*map(f, vals)))
   4386 
   4387         ids = get_group_index(labels, shape, sort=False, xnull=False)

/anaconda3/lib/python3.7/site-packages/pandas/core/frame.py in f(vals)
   4364         def f(vals):
   4365             labels, shape = algorithms.factorize(
-> 4366                 vals, size_hint=min(len(self), _SIZE_HINT_LIMIT))
   4367             return labels.astype('i8', copy=False), len(shape)
   4368 

/anaconda3/lib/python3.7/site-packages/pandas/util/_decorators.py in wrapper(*args, **kwargs)
    176                 else:
    177                     kwargs[new_arg_name] = new_arg_value
--> 178             return func(*args, **kwargs)
    179         return wrapper
    180     return _deprecate_kwarg

/anaconda3/lib/python3.7/site-packages/pandas/core/algorithms.py in factorize(values, sort, order, na_sentinel, size_hint)
    628                                            na_sentinel=na_sentinel,
    629                                            size_hint=size_hint,
--> 630                                            na_value=na_value)
    631 
    632     if sort and len(uniques) > 0:

/anaconda3/lib/python3.7/site-packages/pandas/core/algorithms.py in _factorize_array(values, na_sentinel, size_hint, na_value)
    474     uniques = vec_klass()
    475     labels = table.get_labels(values, uniques, 0, na_sentinel,
--> 476                               na_value=na_value)
    477 
    478     labels = _ensure_platform_int(labels)

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_labels()

TypeError: unhashable type: 'list'

我做错了什么？

Answer 1

据我了解，您的数据框中有列表，而 python 或 Pandas 不能散列列表。如果您曾经尝试将列表用作字典中的键，您可能已经观察到这一点。一个简单的解决方法是将列表转换为可散列的元组。