按特定列中的索引对熊猫数据框进行切片

Question

Assume I have a pandas datafra df and I have the columns A,B,C .

I want to take the index' idx=[1,10,12,17] from column B - how is that done?

I have tried df[idx,"B"], df.iloc[idx,"B"], df.loc[idx,"B"]

Answer 1

You can you .loc or .iloc .

idx = [1,10,12,17]
df = pd.DataFrame(np.random.rand(20, 3), columns=['A', 'B', 'C'])

df.loc[idx, 'B']
df.iloc[idx, 1]

Result:

1     0.532895
10    0.197801
12    0.978466
17    0.847575
Name: B, dtype: float64