How to convert list of model objects to pandas dataframe?

A much cleaner way to to this is to define a to_dict method on your class and then use pandas.DataFrame.from_records

class Signal(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def to_dict(self):
        return {
            'x': self.x,
            'y': self.y,
        }

e.g.

In [87]: signals = [Signal(3, 9), Signal(4, 16)]

In [88]: pandas.DataFrame.from_records([s.to_dict() for s in signals])
Out[88]:
   x   y
0  3   9
1  4  16