pandas 将 Int64Index 转换为 Int
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convert Int64Index to Int
提问by Christopher Jenkins
I'm iterating through a dataframe (called hdf) and applying changes on a row by row basis. hdf is sorted by group_id and assigned a 1 through n rank on some criteria.
我正在遍历一个数据框（称为 hdf）并逐行应用更改。hdf 按 group_id 排序，并根据某些条件分配 1 到 n 等级。
# Groupby function creates subset dataframes (a dataframe per distinct group_id).
grouped = hdf.groupby('group_id')
# Iterate through each subdataframe.
for name, group in grouped:
# This grabs the top index for each subdataframe
index1 = group[group['group_rank']==1].index
# If criteria1 == 0, flag all rows for removal
if(max(group['criteria1']) == 0):
for x in range(rank1, rank1 + max(group['group_rank'])):
hdf.loc[x,'remove_row'] = 1
I'm getting the following error:
我收到以下错误：
TypeError: int() argument must be a string or a number, not 'Int64Index'
I get the same error when I try to cast rank1 explicitly I get the same error:
当我尝试明确地强制转换 rank1 时，我得到了同样的错误我得到了同样的错误：
rank1 = int(group[group['auction_rank']==1].index)
Can someone explain what is happening and provide an alternative?
有人可以解释正在发生的事情并提供替代方案吗？
采纳答案by Evan Wright
The answer to your specific question is that index1is an Int64Index (basically a list), even if it has one element. To get that one element, you can use index1[0].
您的具体问题的答案index1是 Int64Index（基本上是一个列表），即使它只有一个元素。要获得那个元素，您可以使用index1[0].
But there are better ways of accomplishing your goal. If you want to remove all of the rows in the "bad" groups, you can use filter:
但是有更好的方法来实现你的目标。如果要删除“坏”组中的所有行，可以使用filter：
hdf = hdf.groupby('group_id').filter(lambda group: group['criteria1'].max() != 0)
If you only want to remove certain rows within matching groups, you can write a function and then use apply:
如果您只想删除匹配组中的某些行，您可以编写一个函数，然后使用apply：
def filter_group(group):
if group['criteria1'].max() != 0:
return group
else:
return group.loc[other criteria here]
hdf = hdf.groupby('group_id').apply(filter_group)
(If you really like your current way of doing things, you should know that locwill accept an index, not just an integer, so you could also do hdf.loc[group.index, 'remove_row'] = 1).
（如果你真的喜欢你目前的做事方式，你应该知道它loc会接受一个索引，而不仅仅是一个整数，所以你也可以这样做hdf.loc[group.index, 'remove_row'] = 1）。
回答by Hemanth Sharma
call tolist() on Int64Index object. Then the list can be iterated as int values.
在 Int64Index 对象上调用 tolist()。然后可以将列表迭代为 int 值。
