Question

我有一个数据框，其中一列是值列表。我需要选择这些列表不为空的行：

import pandas as pd
data = [('words', ['foo', 'bar', 'baz', 'foobar', 'helter', 'skelter']),
         ('counts', [[1,2,3], [], [5,8], [13,21,34,55], [89], [] ])
         ]
df = pd.DataFrame.from_items(data)
df

Output:
    words   counts
0   foo     [1, 2, 3]
1   bar         []
2   baz         [5, 8]
3   foobar  [13, 21, 34, 55]
4   helter  [89]
5   skelter     []

选择此方法失败：

df[df['counts'] != []]

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-db8067c8ac7b> in <module>()
----> 1 df[df['counts'] != []]

/Users/user/usr/anaconda/lib/python3.5/site-packages/pandas/core/ops.py in wrapper(self, other, axis)
    859 
    860             with np.errstate(all='ignore'):
--> 861                 res = na_op(values, other)
    862             if is_scalar(res):
    863                 raise TypeError('Could not compare %s type with Series' %

/Users/user/usr/anaconda/lib/python3.5/site-packages/pandas/core/ops.py in na_op(x, y)
    763 
    764         if is_object_dtype(x.dtype):
--> 765             result = _comp_method_OBJECT_ARRAY(op, x, y)
    766         else:
    767 

/Users/user/usr/anaconda/lib/python3.5/site-packages/pandas/core/ops.py in _comp_method_OBJECT_ARRAY(op, x, y)
    741             y = y.values
    742 
--> 743         result = lib.vec_compare(x, y, op)
    744     else:
    745         result = lib.scalar_compare(x, y, op)

pandas/_libs/lib.pyx in pandas._libs.lib.vec_compare (pandas/_libs/lib.c:14284)()

ValueError: Arrays were different lengths: 6 vs 0

df.query等其他内容在这种情况下也不起作用。任何想法如何解决这个问题？为什么不能将pandas单元格值与空列表进行比较？

Answer 1

这是一种做到这一点的方法，但是很有效但是有效：

df[ df.counts.str.len() > 0 ]

Pandas：选择行是一列没有空的列表

1 个答案: