Sorting numbers in python

Question

I'm trying to get a function where if you do sort(listname) it would sort all the numbers inside that list from least to greatest.

I'm not sure whats wrong with mine, but I need some help as the output isn't actually least to greatest it does least to greatest for the first two numbers of the number.

Example :

If list has 23, 212, 44 in it than I sort it the output will be like this.

Output :

212,23,44

It should be 23, 44, 212.

Code:

def sort(my_list):
    size = len(my_list)
    for i in range(size):
        for j in range(size-i-1):
            if(my_list[j] > my_list[j+1]):
                tmp = my_list[j]
                my_list[j] = my_list[j+1]
                my_list[j+1] = tmp

More code :

numbers=([])
amount=input("How many numbers are in your list? ")
print("")
counter = 0
ran = 0
while counter < int(amount):
    counter = counter + 1
    ran = ran + 1
    num3 = input(str(ran) + ". Input: ")
    try:
       val = int(num3)
    except ValueError:
       num3 = input(str(ran) + ". Input: ")
    sort(numbers)
    numbers.append(num3)

Aaron Digulla · Accepted Answer · 2013-10-29 16:01:14Z

4

That looks like your list doesn't contain any numbers but strings. Python doesn't try to guess what might be inside of those strings, so you get an odd sort order.

You have two options:

Convert list elements to int before comparing them (if(int(my_list[j]) > int(my_list[j+1])):)
Search this site for python natural sort to get answers how to implement "natural sorting" in Python.

answered Oct 29, 2013 at 16:01

Aaron Digulla

330k111 gold badges626 silver badges840 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

mojo · Accepted Answer · 2013-10-29 16:05:16Z

3

If you just want it sorted, use sorted:

sorted_my_list = sorted(my_list,key=int)

Or to sort it, in place, use

my_list.sort(key=int)

If you want to fix your program, turn my_list into ints or at least compare integers

if ( int(my_list[j]) > int(my_list[j+1])):

Also, you can swap two variables in one statement:

my_list[j],my_list[j+1] = my_list[j+1],my_list[j]

answered Oct 29, 2013 at 16:05

mojo

4,19219 silver badges29 bronze badges

Comments

Christian Tapia · Accepted Answer · 2013-10-29 16:06:31Z

0

I just used your code (Just added a return statement). And it returns the expected values:

def sort(my_list):
    size = len(my_list)
    for i in range(size):
        for j in range(size-i-1):
            if(my_list[j] > my_list[j+1]):
                tmp = my_list[j]
                my_list[j] = my_list[j+1]
                my_list[j+1] = tmp
    return my_list # Note I added this return statement

print sort([23,212,44])
>>> 
[23, 44, 212]

edited Oct 29, 2013 at 16:06

answered Oct 29, 2013 at 16:00

Christian Tapia

34.2k7 gold badges58 silver badges73 bronze badges

1 Comment

user2812028 Over a year ago

I get this: 212,23,44... Weird.

Collectives™ on Stack Overflow

Sorting numbers in python

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related