Question
In the pandas library many times there is an option to change the object
inplace such as with the following statement...
df.dropna(axis='index', how='all', inplace=True)
I am curious what is being returned as well as how the object is handled when
inplace=True is passed vs. when inplace=False.
Are all operations modifying self when inplace=True? And when
inplace=False is a new object created immediately such as new_df = self
and then new_df is returned?
If you are trying to close a question where someone should use inplace=True
and hasn't, consider replace() method not working on Pandas
DataFrame instead.
Answer
When inplace=True is passed, the data is renamed in place (it returns
nothing), so you'd use:
df.an_operation(inplace=True)
When inplace=False is passed (this is the default value, so isn't
necessary), performs the operation and returns a copy of the object, so you'd
use:
df = df.an_operation(inplace=False)
