How to convert pandas single column data frame to series or numpy vector [duplicate]

You can simply index the series you want. Example –

tdf['s1']

Demo –

In [24]: tdf =  pd.DataFrame({'s1' : [0,1,23.4,10,23]})

In [25]: tdf['s1']
Out[25]:
0     0.0
1     1.0
2    23.4
3    10.0
4    23.0
Name: s1, dtype: float64

In [26]: tdf['s1'].shape
Out[26]: (5,)

If you want the values in the series as numpy array, you can use .values accessor , Example –

In [27]: tdf['s1'].values
Out[27]: array([  0. ,   1. ,  23.4,  10. ,  23. ])