python pandas select both head and tail

fu xue picture fu xue · Feb 28, 2017 · Viewed 20k times · Source

For a DataFrame in Pandas, how can I select both the first 5 values and last 5 values?

For example

In [11]: df
Out[11]: 
        A  B  C
2012-11-29  0  0  0
2012-11-30  1  1  1
2012-12-01  2  2  2
2012-12-02  3  3  3
2012-12-03  4  4  4
2012-12-04  5  5  5
2012-12-05  6  6  6
2012-12-06  7  7  7
2012-12-07  8  8  8
2012-12-08  9  9  9

How to show the first two and the last two rows?

Answer

jezrael picture jezrael · Feb 28, 2017

You can use iloc with numpy.r_:

print (np.r_[0:2, -2:0])
[ 0  1 -2 -1]

df = df.iloc[np.r_[0:2, -2:0]]
print (df)
            A  B  C
2012-11-29  0  0  0
2012-11-30  1  1  1
2012-12-07  8  8  8
2012-12-08  9  9  9

df = df.iloc[np.r_[0:4, -4:0]]
print (df)
            A  B  C
2012-11-29  0  0  0
2012-11-30  1  1  1
2012-12-01  2  2  2
2012-12-02  3  3  3
2012-12-05  6  6  6
2012-12-06  7  7  7
2012-12-07  8  8  8
2012-12-08  9  9  9