Creating an empty DataFrame as a default parameter

Question

I am trying to create a python function that plots the data from a DataFrame. The parameters should either be just the data. Or the data and the standard deviation.

As a default parameter for the standard deviation, I want to use an empty DataFrame.

def plot_average(avg_df, stdev=pd.DataFrame()):           
    if not stdev.empty:
        ...
    ...

But implementing it like that gives me the following error message:

TypeError: 'module' object is not callable

How can an empty DataFrame be created as a default parameter?

I run the code you posted, and it works fine. Your error comes from something you didn't post. — Aryerez
– Aryerez, Commented Nov 18, 2019 at 9:49
your code works have a look at it for better practice stackoverflow.com/questions/13784192/… — nithin
– nithin, Commented Nov 18, 2019 at 9:52
I think you are right. But for me the code doesn't work if I remove everything from the function. In the same file I have another function, but that one works just fine — Fabian Bachl
– Fabian Bachl, Commented Nov 18, 2019 at 10:41

sidiyahya · Accepted Answer · 2020-05-28 10:59:39Z

3

for a default empty dataframe :

def f1(my_df=None):
    if(my_df is None):
        my_df = pd.DataFrame()
    #stuff to do if it's not empty
    if(len(my_df) != 0):
        print(my_df)
    elif(len(my_df) == 0):
        print("Nothing")

answered May 28, 2020 at 10:59

sidiyahya

311 bronze badge

Sign up to request clarification or add additional context in comments.

Comments

KPLauritzen · Accepted Answer · 2019-11-18 09:49:48Z

2

A DataFrame is mutable, so a better approach is to default to None and then assign the default value in the function body. See https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments

answered Nov 18, 2019 at 9:49

KPLauritzen

1,88916 silver badges23 bronze badges

Comments

Fabian Bachl · Accepted Answer · 2019-11-18 10:59:52Z

0

The problem lies not in the creation of a new DataFrame but in the way the function was called. I use pycharm scientific. In which I had the function call written in a block. Executing this block called the function which was, i presume, not compiled.

Executing the whole programm made it possible to call the function

answered Nov 18, 2019 at 10:59

Fabian Bachl

3011 gold badge4 silver badges12 bronze badges

Collectives™ on Stack Overflow

Creating an empty DataFrame as a default parameter

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related