Trying to append an input number in a list function is returning none

Question

I need to return a list of numbers input by the user.

I have tried to insert an empty list and then using the .append function to append the input value to the list.

def ask_a_number():
    trials = []
    playernumber = int(input('Guess a number: '))
    trials = trials.append(playernumber)
    return playernumber, trials
ask_a_number()

Lets say I want to input 5. So I want the function to return 5 and also a list trials = [5]. Next time when I input 10, the function should return trials = [5,10].

append does not return anything, it modifies the list inplace. Try changing to: `trials.append(playernumber)` — Dani Mesejo, Dec 31 '18 at 01:31

score 1 · Answer 1 · answered Dec 31 '18 at 01:33

1

Change

trials = trials.append(playernumber)

to

trials.append(playernumber)

Since list.append returns None (it alters the state of trials instead) and you reassign its return value to trials, you get None in your returned tuple.

answered Dec 31 '18 at 01:33

Paul Rooney

20,879
9
40
61

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Got it. Thanks ! :) – Prashant Mishra Dec 31 '18 at 03:39

Sun Voyager · Answer 2 · 2018-12-31T03:39:15.613

1

 def ask_a_number():
       trials = []
       while True:
           playernumber = int(input('Guess a number: '))
           trials.append(playernumber)
           if playernumber==0:
             break
       print(playernumber, trials)
       return 
 ask_a_number()

edited Dec 31 '18 at 03:39

answered Dec 31 '18 at 03:31

Sun Voyager

147
2
12

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Please add some brief that what you did special. – Farhana Naaz Ansari Dec 31 '18 at 05:26
1

i think you must calm down – Sun Voyager Jan 01 '19 at 20:41

score 0 · Accepted Answer · answered Dec 31 '18 at 01:33

append() doesn't return anything. It is designed to do in-place modification. So just do the following:

def ask_a_number(trials=None):
    trials = trials or []
    playernumber = int(input('Guess a number: '))
    trials.append(playernumber)
    return playernumber, trials
ask_a_number()

I've also added a default value for trials so that if you want to do this in a loop, you can like so:

trials = []

for i in range(6):
    player, trials = ask_a_number(trials)

Got it.. Thanks ! :) – Prashant Mishra Dec 31 '18 at 03:38 — Prashant Mishra, Dec 31 '18 at 03:38

Trying to append an input number in a list function is returning none

3 Answers3