How can I extract the nth row of a pandas data frame as a pandas data frame?

Question

Suppose a Pandas data frame looks like:

X_test.head(4)     BoxRatio  Thrust  Velocity  OnBalRun  vwapGain 5     -0.163  -0.817     0.741     1.702     0.218 8      0.000   0.000     0.732     1.798     0.307 11     0.417  -0.298     2.036     4.107     1.793 13     0.054  -0.574     1.323     2.553     1.185 

How can I extract the third row (as row3) as a pd data frame? In other words, row3.shape should be (1,5) and row3.head() should be:

 0.417  -0.298     2.036     4.107     1.793 

Answer 1

Use .iloc with double brackets to extract a DataFrame, or single brackets to pull out a Series.

>>> import pandas as pd >>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]}) >>> df    col1  col2 0     1     3 1     2     4 >>> df.iloc[[1]]  # DataFrame result    col1  col2 1     2     4 >>> df.iloc[1]  # Series result col1    2 col2    4 Name: 1, dtype: int64 

This extends to other forms of DataFrame indexing as well, namely .loc and .__getitem__():

>>> df.loc[:, ['col2']]    col2 0     3 1     4  >>> df[['col2']]    col2 0     3 1     4