DataFrame.drop 不会删除 Pandas 中的预期行
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DataFrame.drop not dropping expected rows in Pandas
提问by Chris Fonnesbeck
I have a Pandas DataFrame that includes rows that I want to drop based on values in a column "population":
我有一个 Pandas DataFrame，其中包含我想根据“population”列中的值删除的行：
data['population'].value_counts()
general population 21
developmental delay 20
sibling 2
general population + developmental delay 1
dtype: int64
here, I want to drop the two rows that have siblingas the value. So, I believe the following should do the trick:
在这里，我想删除具有sibling作为值的两行。所以，我相信以下应该可以解决问题：
data = data.drop(data.population=='sibling', axis=0)
It does drop 2 rows, as you can see in the resulting value counts, but they were notthe rows with the specified value.
正如您在结果值计数中看到的那样，它确实删除了 2 行，但它们不是具有指定值的行。
data.population.value_counts()
developmental delay 20
general population 19
sibling 2
general population + developmental delay 1
dtype: int64
Any idea what is going on here?
知道这里发生了什么吗？
回答by joaquin
dataFrame.dropaccepts an index (list of labels) as a parameter, not a mask.
To use dropyou should do:
dataFrame.drop接受索引（标签列表）作为参数，而不是掩码。
要使用drop你应该这样做：
data = data.drop(data.index[data.population == 'sibling'])
however it is much simpler to do
但是做起来要简单得多
data = data[data.population != 'sibling']
