Attempt to access dataframe column displays “<bound method NDFrame.xxx…”

Question

I create DataFrame object in Jupyter notebook:

data = {\'state\':[\'Ohio\',\'Ohio\',\'Ohio\',\'Nevada\',\'Nevada\'],
       \'year\':[2000, 2001, 2002, 2000,         


        

Answer 1

pop is a dataframe level function. The takeaway here is try to avoid using the . accessor to access columns. There are many dataframe attributes and functions that might clash with your column names, in which case the . will invoke those instead of your columns.

You want to use the [..] dict accessor instead:

frame['pop']
0    1.5
1    2.0
2    3.6
3    2.4
4    2.9
Name: pop, dtype: float64

---

If you want to use pop, you can. This is how:

frame.pop('pop') 
0    1.5
1    2.0
2    3.6
3    2.4
4    2.9
Name: pop, dtype: float64

frame
    state  year
0    Ohio  2000
1    Ohio  2001
2    Ohio  2002
3  Nevada  2000
4  Nevada  2001

Do note that this modifies the original dataframe, so don't do it unless you're trying to remove columns.

Answer 2

The way I am using ...eval

frame.eval('pop')
Out[108]: 
0    1.5
1    2.0
2    3.6
3    2.4
4    2.9
dtype: float64

Answer 3

pop is a method of pandas.DataFrame. You need to use frame['pop']