Get rows from DataFrame based on array of indices

Question

I have an array with numbers which corresponds to the row numbers that need to be selected from a DataFrame. For example, arr = np.array([0,0,1,1]) and the DataFrame is seen below. arr is the row number and not the index.

Index   A   B   C   D
3      10   0   0   0
4      5    2   0   0

Using arr I would like to produce a DataFrame that looks like this

  Index    A    B   C   D
    3      10   0   0   0
    3      10   0   0   0
    4      5    2   0   0
    4      5    2   0   0

akuiper · Accepted Answer · 2016-09-11 15:13:10Z

8

You can use iloc with integer indexing:

df.iloc[[0,0,1,1], :]   # or df.iloc[arr, :]

#    A  B   C   D
#Index              
#3  10  0   0   0
#3  10  0   0   0
#4   5  2   0   0
#4   5  2   0   0

answered Sep 11, 2016 at 15:13

akuiper

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1 Comment

Ami Tavory Over a year ago

Nice. I think df.iloc[arr] also works in this case.

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