Accept args and put in a python list only even numbers

Question

I have written the following Python code, but its throwing me an error

    def myfunc(*args):
         mylist = list()
         for num in args:
              if num%2 ==0:
              mylist = mylist.append(num)
        return mylist

It throws me the following error [-2, 4]!= None.

What is wrong with the above code?

(1) Repair indentation of your code. (2) `list.append` returns `None`, it modifies the list in-place. — Michael Butscher, Oct 10 '19 at 03:17

score 2 · Answer 1 · answered Oct 10 '19 at 03:16

mylist = mylist.append(num)

It is a convention in Python that methods that mutate the object return None. list.append is such a function: it will add an element to the list, then return None. By reassignment, your mylist becomes None; which obviously then breaks in the next iteration, as None is not capable of being appended to.

Change the line to just

mylist.append(num)

score 1 · Accepted Answer · answered Oct 10 '19 at 03:23

1

Your code has indent problem. It works fine if you indent it properly. like this:

def myfunc(x):
    mylist = list()
    for num in x:
        if num%2 ==0:
            mylist.append(num)
    return mylist

answered Oct 10 '19 at 03:23

Usama

42
6

score 0 · Answer 3 · answered Oct 10 '19 at 03:21

0

def myfunc(*args):
        mylist = list()
        for num in args:
                if num%2 == 0:
                        mylist.append(num)

        return mylist

After correcting indentation and removing assignment of mylist to itself - above code works.

answered Oct 10 '19 at 03:21

Pravar Jawalekar

605
1
6
18

Thanks for all the answers. It worked with the correct indentation as suggested. – Raghu Oct 10 '19 at 03:29

score 0 · Answer 4 · answered Oct 10 '19 at 03:22

0

def myfunc(*args):
    mylist = list()
    for num in args:
        if num%2 == 0:
            mylist.append(num)
    return mylist

I think it's because you are using .append in the wrong way.

answered Oct 10 '19 at 03:22

Giallo

96
4

score 0 · Answer 5 · answered Oct 10 '19 at 03:25

0

try this!

def myfunc(*args):
    mylist = []
    for arg in args:
        if num % 2 == 0:
            mylist.append(arg)
    return mylist

make sure to call it this way

myfunc(-2, 4)

answered Oct 10 '19 at 03:25

mindless-overflow

152
8

Accept args and put in a python list only even numbers

5 Answers5