与列表的Pandas DataFrame列的比较 [英] Comparisons with Pandas DataFrame columns of lists
本文介绍了与列表的Pandas DataFrame列的比较的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个这样的数据框df:
I have a dataframe df like this:
col1 | col2
a | [1,2]
b | [3,4]
c | [3,9]
我想基于匹配的输入数组获取行,所以如果我有数组[1,2],我可以得到:
I want to get the row based on a matching input array, so if I have the array [1,2], I can get:
col1 | col2
a | [1,2]
当我尝试使用此公式执行此操作时,它不起作用:
When I try to do this using this formula, it doesn't work:
df.loc[df['Col2'] == [1,2]]
Error: Lengths must match to compare
推荐答案
真正的错误原因是并非所有列表的大小都相同,这会导致DataFrame.eq
出现问题.
The real cause of your error was that not all lists are of the same size, this causes issues with DataFrame.eq
.
解决此问题的最佳方法是使用列表推导构建一个布尔掩码,然后使用它索引到df
:
The best approach to tackling this is to build a boolean mask using a list comprehension and then use it to index into df
:
df[[v == [1, 2] for v in df['col2'].tolist()]]
另一种替代方法是df.apply
,但这并不比这快.
Another alternative is df.apply
, but that isn't nearly as fast as this.
这篇关于与列表的Pandas DataFrame列的比较的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文