pandas 查询单输出

Question

I have a pandas dataframe (called smalls) that is repurposed several times to create several network diagrams from a dataset. I am trying to set the color of the nodes in one of the diagrams based on entity type and need to query the original dataframe. However, when I do so it results in a series, which I then cannot perform a comparison on. How can I modify the first line below to only give me the first entry from the dataframe (all of the others will be the same)?

temp=smalls.Role[smalls.Entity==big_nodes_order[i]]

print(temp)
10    Threat
11    Threat
12    Threat
Name: Role, dtype: object

Answer 1

I think you can use iloc or iat :

temp=smalls.Role[smalls.Entity==big_nodes_order[i]]
print temp
10    Threat
11    Threat
12    Threat
Name: Role, dtype: object

print temp.iloc[0]
Threat

print temp.iat[0]
Threat

print temp.iloc[:1]
10    Threat
Name: Role, dtype: object

Answer 2

或者，您可以使用.head()方法：

temp=smalls.Role[smalls.Entity==big_nodes_order[i]].head(1)