Multiple inputs from one input

Question

I'm writing a function to append an input to a list. I want it so that when you input 280 2 the list becomes ['280', '280'] instead of ['280 2'].

score 8 · Accepted Answer · edited May 23 '17 at 12:15

8

>>> number, factor = input().split()
280 2
>>> [number]*int(factor)
['280', '280']

Remember that concatenating a list with itself with the * operator can have unexpected results if your list contains mutable elements - but in your case it's fine.

edit:

Solution that can handle inputs without a factor:

>>> def multiply_input():
...     *head, tail = input().split()
...     return head*int(tail) if head else [tail]
... 
>>> multiply_input()
280 3
['280', '280', '280']
>>> multiply_input()
280
['280']

Add error checking as needed (for example for empty inputs) depending on your use case.

edited May 23 '17 at 12:15

Community

1
1

answered Apr 16 '16 at 11:40

timgeb

76,762
20
123
145

I like it, but it appears it runs into an error when you only enter 280, I could use ugly code like I usually do to fix this but do you know of any sleek solution? – Carl Groth Apr 16 '16 at 11:46

Taylan · Answer 2 · 2016-04-20T10:29:56.210

2

from itertools import repeat

mes=input("please write your number and repetitions:").split()
listt= []
listt.extend(repeat(int(mes[0]), int(mes[1]))   

#repeat(object [,times]) -> create an iterator which returns the object
#for the specified number of times.  If not specified, returns the object
#endlessly.

edited Apr 20 '16 at 10:29

answered Apr 16 '16 at 11:40

Taylan

736
1
5
14

Please consider explaining the rationale behind your code to make it easier for those who are trying to learn from it. – Reti43 Apr 16 '16 at 19:59
1

Thank you! I was going insane trying to .append my inputs when I (unbeknownst to me) actually wanted to .extend them. – Carl Groth Apr 17 '16 at 11:20

Eli Korvigo · Answer 3 · 2016-04-17T20:52:18.643

2

You can handle the case with unspecified number of repetitions by extending the parsed input with a list containing 1. You can then slice the list to leave the first 2 items (in case the number of repetitions was provided, that [1] will be discarded)

number, rep = (input().split() + [1])[:2]
[number] * int(rep)

edited Apr 17 '16 at 20:52

answered Apr 16 '16 at 11:50

Eli Korvigo

10,265
6
47
73

A bit of text would help the reader understand quicker your solution. – Laur Ivan Apr 16 '16 at 14:22

score 0 · Answer 4 · answered Apr 16 '16 at 13:10

This code provides exception handling against no second number being provided with in put.

def addtolist():
    number = input("Enter number: ")
    try:
        factor = input("Enter factor: ")
    except SyntaxError:
        factor = 1
    for i in range(factor):
        listname.append(number)

Multiple inputs from one input

4 Answers4