I have the following data frame:
pa=pd.DataFrame({'a':np.array([[1.,4.],[2.],[3.,4.,5.]])})
Now what should I do if I want to select the column 'a' and then only a particular element (i.e. first: 1., 2., 3.)
What do I need to add to the following:
pa.loc[:,['a']]
Can anyone provide the solution?