Python：使用 object 作为参数（例如方法（XXX）与以下语法：XXX.method（））之间有区别吗？

Question

Sorry that I do not yet have the vocabulary to express this question properly.

For example:

# Import sas7bdat package
from sas7bdat import SAS7BDAT

# Save file to a DataFrame: df_sas
with SAS7BDAT('sales.sas7bdat') as file:
    df_sas = file.to_data_frame()

# Print head of DataFrame
print(df_sas.head())

and

# Save file to a DataFrame: df_sas
with SAS7BDAT('sales.sas7bdat') as file:
    df_sas = SAS7BDAT.to_data_frame(file)

# Print head of DataFrame
print(df_sas.head())

both produce the same result. Are they generally equivalent or is this a special circumstance?

Answer 1

I wouldn't call it a special case but rather indirect.

You are creating an object file that is an instance of that class SAS7BDAT with with SAS7BDAT('sales.sas7bdat') as file: and then you are using the Class method to_data_frame from the Class instead from the instance directly.

Answer 2

It is really a special circumstance and maybe the second code has another side-effect you cant see yet.