Using a function inside a function and its variable as a variable

Question

Assume for example that I am writing a function for the following code (in pandas module):

myData.sort_values(by=myVariable, ascending=False)

Now, I want to create a function whose variables are data, variable and ascending.

sort(data=mydata, variable=myvariable, ascending=False)

The below function gives an error, because whether ascending is true or false is not given in second line:

def sort(data,variable,ascending=False):
    data.sort_values(by=variable, ascending)

Although it would work, I do not want to change variable name such as:

def sort(data,variable,asc=False):
    data.sort_values(by=variable, ascending=asc)

One last approach would be to create a variable inside the function:

def sort(data,variable,ascending=False):
    asc = ascending
    data.sort_values(by=variable, ascending=asc)

but it looks somewhat confusing. Is there an alternative approach to use the same variable in this case?

Note: the question is not related with pandas module, it is just an example.

Edit: I have clearly stated my problem and showed what I have tried. I did not understand the reason for the downvote.

There are functions in python that can take positional arguments and keyword only arguments. If there is such a keyword only constraint set on the arguments, you can't call it as positional arguments. Have a look at [this question](https://stackoverflow.com/questions/54252179/how-to-create-a-python-function-which-take-only-positional-arguments-and-no-keyw). — Diptangsu Goswami, Oct 19 '19 at 08:32

score 3 · Accepted Answer · answered Oct 19 '19 at 08:31

3

have you tried:

def sort(data,variable,ascending=False):
    data.sort_values(by=variable, ascending=ascending)

answered Oct 19 '19 at 08:31

Nick Martin

731
3
17

This did not produce an error, but it didn't work either – ThePortakal Oct 19 '19 at 08:47
Then you should open a new question for that error and accept this answer as correct – Nick Martin Oct 19 '19 at 09:45
1

Thanks, I tried this with another dataset and it works. – ThePortakal Oct 19 '19 at 10:40

score 0 · Answer 2 · answered Oct 19 '19 at 09:37

The below function gives an error, because whether ascending is true or false is not given in second line:

def sort(data,variable,ascending=False):
    data.sort_values(by=variable, ascending)

No; it gives an error because positional arguments cannot come after keyword arguments. Like the error message says: SyntaxError: positional argument follows keyword argument.

The way to fix this is as in the other answer, using ascending=ascending. The idea is that the arguments for the function call are in a separate namespace from the current local variables.

If it "didn't work", then you need to ask a new question and properly explain the expected and actual results, with a complete example that other users can test locally.

Using a function inside a function and its variable as a variable

2 Answers2