如何使用Pandas获取数据集中Score列负值的索引？

Got it, let's walk through how to get the indices of negative values in your Score column.

First, let's recap your sample data to make sure we're on the same page:

sdf.head()
Out[65]:
Score
0 161
1 238
2 -53
3 83
4 171

Method 1: Boolean Indexing + .index #

The simplest way is to use a boolean mask to filter rows where Score is negative, then extract their indices:

# Create a boolean mask for negative values
negative_mask = sdf['Score'] < 0

# Filter the dataframe and get the indices
negative_indices = sdf[negative_mask].index

# If you want the indices as a list instead of an Index object
negative_indices_list = negative_indices.tolist()

Running this on your sample data would give:

• negative_indices → Int64Index([2], dtype='int64')
• negative_indices_list → [2]

Method 2: Using .loc (Concise Alternative) #

You can also condense this into a single line with .loc:

negative_indices = sdf.loc[sdf['Score'] < 0].index

This works exactly the same as the first method—it's just a more compact way to write it.

Quick Breakdown #

• The boolean mask sdf['Score'] < 0 generates a Series where each entry is True if the corresponding Score is negative, and False otherwise.
• Slicing the dataframe with this mask keeps only the rows where the mask is True.
• Calling .index on the filtered subset pulls out the original indices of those negative-value rows.

内容的提问来源于stack exchange，提问作者IndigoChild