why sort in python is not working?

Question

code:
list=['1','85863','432','93','549834']
list.sort()
print (list)

Actual output:
>>> 
['1', '432', '549834', '85863', '93']
#why sort is not working
Expected output:
['1','93','432','83863','549834']

I have tried other sort operations also but they are displaying same output. when i tried to read list from keyboard input they are reading only strings but not int please help me why?

related: http://stackoverflow.com/questions/20449427/how-can-i-read-inputs-as-integers-in-python — NightShadeQueen, Jul 24 '15 at 20:08
Your expected output is sorted neither alphabetically nor numerically. — TigerhawkT3, Jul 24 '15 at 20:10
that looks sorted to me. (contrary to your expected output, for which I can't find any sorting logic. except by sum of the digits, maybe?) — njzk2, Jul 24 '15 at 20:21
You can compile brain teasers from some of these downvoted questions you see on SO — bakkal, Jul 24 '15 at 20:29
Fortunately, SO's mechanical Turk is good at brute-forcing these brain teasers. — TigerhawkT3, Jul 24 '15 at 20:46

bakkal · Accepted Answer · 2015-07-24T20:14:45.003

2

when i tried to read list from keyboard input they are reading only strings but not int please help me why

if x is a string, just use int(x) to convert to int

You're sorting strings (text), not by numerical values like integers

For your expected output you have to convert to ints first

my_list= ['1','85863','432','93','549834']
my_list = [int(x) for x in my_list]

Now you can sort numerically, and get a list of ints

my_list.sort()

_{N.B. avoid using list as variable name, it is a Python built-in}

edited Jul 24 '15 at 20:14

answered Jul 24 '15 at 20:05

bakkal

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His expected output isn't in numerical order either. – BrenBarn Jul 24 '15 at 20:06
Hmm yeah also not clear if expected output is a list of ints or strings again – bakkal Jul 24 '15 at 20:09

score 2 · Answer 2 · answered Jul 24 '15 at 20:10

2

I presume you want to sort by the sum to match your expected output:

l = ['1','85863','432','93','549834']

l.sort(key=lambda x: sum(map(int,x)))

print(l)
['1', '432', '93', '83863', '549834']

answered Jul 24 '15 at 20:10

Padraic Cunningham

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Ha! nice pattern guessing going on! – bakkal Jul 24 '15 at 20:12
@bakkal, it is the only thing that makes any sense, sorting by length,last digit, first digit or anything else would not give the expected output – Padraic Cunningham Jul 24 '15 at 20:14
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Oh I liked your solution, let's just hope the OP just didn't screwed up the expected output just like they screwed the question :P – bakkal Jul 24 '15 at 20:19
@bakkal, that is a distinct possibility! – Padraic Cunningham Jul 24 '15 at 20:20

score 1 · Answer 3 · answered Jul 24 '15 at 20:08

1

You need to first convert the strings to int.

list = [int(ele) for ele in list]
list.sort()
print list

answered Jul 24 '15 at 20:08

Aiken

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score 0 · Answer 4 · answered Jul 24 '15 at 20:17

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Without int:

lst = ['1','85863','432','93','549834']
lst.sort()
lst.sort(key=len)
print(lst)

This give:

['1', '93', '432', '85863', '549834']

And if you want integers…

my_int = int(input())

answered Jul 24 '15 at 20:17

Clodion

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score 0 · Answer 5 · answered Feb 06 '17 at 15:08

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I simply missed the logic of converting a string into int.By default python input will be taken as a string. so,we can use any method mentioned in the answers to convert in to string and then sort() method works succesufully over int

answered Feb 06 '17 at 15:08

Pavan Nath

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why sort in python is not working?

5 Answers5