Custom comparison for integer strings












1














For the input 3 30 34 5 9, the expected largest number output is: 9534330



Any inputs why the sorted is returning the same result as input: 3303459?



import functools



def compare(item1, item2):

    return int(item1 + item2) - int(item2 + item1)



inputList = input().split()

sorted(inputList, key=functools.cmp_to_key(compare))

max = "".join([ x for x in inputList])

print(max)





python python-3.x







share|improve this question




















  • 4




    Because sorted returns a new list.
    – jonrsharpe
    Nov 20 at 7:56


















1














For the input 3 30 34 5 9, the expected largest number output is: 9534330



Any inputs why the sorted is returning the same result as input: 3303459?



import functools



def compare(item1, item2):

    return int(item1 + item2) - int(item2 + item1)



inputList = input().split()

sorted(inputList, key=functools.cmp_to_key(compare))

max = "".join([ x for x in inputList])

print(max)





python python-3.x







share|improve this question




















  • 4




    Because sorted returns a new list.
    – jonrsharpe
    Nov 20 at 7:56
















1












1








1







For the input 3 30 34 5 9, the expected largest number output is: 9534330



Any inputs why the sorted is returning the same result as input: 3303459?



import functools



def compare(item1, item2):

    return int(item1 + item2) - int(item2 + item1)



inputList = input().split()

sorted(inputList, key=functools.cmp_to_key(compare))

max = "".join([ x for x in inputList])

print(max)





python python-3.x







share|improve this question















For the input 3 30 34 5 9, the expected largest number output is: 9534330



Any inputs why the sorted is returning the same result as input: 3303459?



import functools



def compare(item1, item2):

    return int(item1 + item2) - int(item2 + item1)



inputList = input().split()

sorted(inputList, key=functools.cmp_to_key(compare))

max = "".join([ x for x in inputList])

print(max)





python python-3.x




python python-3.x






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 20 at 8:00









jonrsharpe

76.7k11101208




76.7k11101208










asked Nov 20 at 7:54









Rock

8117




8117








  • 4




    Because sorted returns a new list.
    – jonrsharpe
    Nov 20 at 7:56
















  • 4




    Because sorted returns a new list.
    – jonrsharpe
    Nov 20 at 7:56










4




4




Because sorted returns a new list.
– jonrsharpe
Nov 20 at 7:56






Because sorted returns a new list.
– jonrsharpe
Nov 20 at 7:56














3 Answers
3






active

oldest

votes


















1














The reason is either because you are sorting the list in the wrong order and you did not use the sorted list. Currently, you are sorting the list in an ascending order by the first digit. In addition to that, sorted() function returns a new list, so you need to save that in a variable.



You can fix that by either using the reverse() on the sorted list



import functools



def compare(item1, item2):

    return int(item1 + item2) - int(item2 + item1)



inputList = input().split()

inputList = sorted(inputList, key=functools.cmp_to_key(compare))

inputList.reverse()

max = "".join([ x for x in inputList])

print(max)


Or switch operation in the compare() function



import functools



def compare(item1, item2):

    return int(item2 + item1) - int(item1 + item2)



inputList = input().split()

inputList = sorted(inputList, key=functools.cmp_to_key(compare))

max = "".join([ x for x in inputList])

print(max)





share|improve this answer





























    1














    For exhaustiveness, you can also set the order argument in the sorted() function:
    import functools



    def compare(item1, item2):
    
    return int(item1 + item2) - int(item2 + item1)
    

    
input_list = input().split(",")
    
custom_sorted_list = sorted(input_list, key=functools.cmp_to_key(compare), reverse=True)
    
max = "".join([ x for x in custom_sorted_list])
    
print(max)





    share|improve this answer





























      0














      The sorted function returns the list in ascending order.



      But, as you only want the largest number, it is even easier:



      import itertools
      

      
input_list = [3, 30, 34, 5, 9]
      

      
answer = max(map("".join, itertools.permutations(map(str, input_list))))
      

      
print(answer)





      share|improve this answer





















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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        1














        The reason is either because you are sorting the list in the wrong order and you did not use the sorted list. Currently, you are sorting the list in an ascending order by the first digit. In addition to that, sorted() function returns a new list, so you need to save that in a variable.



        You can fix that by either using the reverse() on the sorted list



        import functools
        

        
def compare(item1, item2):
        
    return int(item1 + item2) - int(item2 + item1)
        

        
inputList = input().split()
        
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
        
inputList.reverse()
        
max = "".join([ x for x in inputList])
        
print(max)


        Or switch operation in the compare() function



        import functools
        

        
def compare(item1, item2):
        
    return int(item2 + item1) - int(item1 + item2)
        

        
inputList = input().split()
        
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
        
max = "".join([ x for x in inputList])
        
print(max)





        share|improve this answer


























          1














          The reason is either because you are sorting the list in the wrong order and you did not use the sorted list. Currently, you are sorting the list in an ascending order by the first digit. In addition to that, sorted() function returns a new list, so you need to save that in a variable.



          You can fix that by either using the reverse() on the sorted list



          import functools
          

          
def compare(item1, item2):
          
    return int(item1 + item2) - int(item2 + item1)
          

          
inputList = input().split()
          
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
          
inputList.reverse()
          
max = "".join([ x for x in inputList])
          
print(max)


          Or switch operation in the compare() function



          import functools
          

          
def compare(item1, item2):
          
    return int(item2 + item1) - int(item1 + item2)
          

          
inputList = input().split()
          
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
          
max = "".join([ x for x in inputList])
          
print(max)





          share|improve this answer
























            1












            1








            1






            The reason is either because you are sorting the list in the wrong order and you did not use the sorted list. Currently, you are sorting the list in an ascending order by the first digit. In addition to that, sorted() function returns a new list, so you need to save that in a variable.



            You can fix that by either using the reverse() on the sorted list



            import functools
            

            
def compare(item1, item2):
            
    return int(item1 + item2) - int(item2 + item1)
            

            
inputList = input().split()
            
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
            
inputList.reverse()
            
max = "".join([ x for x in inputList])
            
print(max)


            Or switch operation in the compare() function



            import functools
            

            
def compare(item1, item2):
            
    return int(item2 + item1) - int(item1 + item2)
            

            
inputList = input().split()
            
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
            
max = "".join([ x for x in inputList])
            
print(max)





            share|improve this answer












            The reason is either because you are sorting the list in the wrong order and you did not use the sorted list. Currently, you are sorting the list in an ascending order by the first digit. In addition to that, sorted() function returns a new list, so you need to save that in a variable.



            You can fix that by either using the reverse() on the sorted list



            import functools
            

            
def compare(item1, item2):
            
    return int(item1 + item2) - int(item2 + item1)
            

            
inputList = input().split()
            
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
            
inputList.reverse()
            
max = "".join([ x for x in inputList])
            
print(max)


            Or switch operation in the compare() function



            import functools
            

            
def compare(item1, item2):
            
    return int(item2 + item1) - int(item1 + item2)
            

            
inputList = input().split()
            
inputList = sorted(inputList, key=functools.cmp_to_key(compare))
            
max = "".join([ x for x in inputList])
            
print(max)






            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Nov 20 at 8:07









            Andreas

            1,7961618




            1,7961618

























                1














                For exhaustiveness, you can also set the order argument in the sorted() function:
                import functools



                def compare(item1, item2):
                
    return int(item1 + item2) - int(item2 + item1)
                

                
input_list = input().split(",")
                
custom_sorted_list = sorted(input_list, key=functools.cmp_to_key(compare), reverse=True)
                
max = "".join([ x for x in custom_sorted_list])
                
print(max)





                share|improve this answer


























                  1














                  For exhaustiveness, you can also set the order argument in the sorted() function:
                  import functools



                  def compare(item1, item2):
                  
    return int(item1 + item2) - int(item2 + item1)
                  

                  
input_list = input().split(",")
                  
custom_sorted_list = sorted(input_list, key=functools.cmp_to_key(compare), reverse=True)
                  
max = "".join([ x for x in custom_sorted_list])
                  
print(max)





                  share|improve this answer
























                    1












                    1








                    1






                    For exhaustiveness, you can also set the order argument in the sorted() function:
                    import functools



                    def compare(item1, item2):
                    
    return int(item1 + item2) - int(item2 + item1)
                    

                    
input_list = input().split(",")
                    
custom_sorted_list = sorted(input_list, key=functools.cmp_to_key(compare), reverse=True)
                    
max = "".join([ x for x in custom_sorted_list])
                    
print(max)





                    share|improve this answer












                    For exhaustiveness, you can also set the order argument in the sorted() function:
                    import functools



                    def compare(item1, item2):
                    
    return int(item1 + item2) - int(item2 + item1)
                    

                    
input_list = input().split(",")
                    
custom_sorted_list = sorted(input_list, key=functools.cmp_to_key(compare), reverse=True)
                    
max = "".join([ x for x in custom_sorted_list])
                    
print(max)






                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Nov 20 at 8:11









                    leoburgy

                    1086




                    1086























                        0














                        The sorted function returns the list in ascending order.



                        But, as you only want the largest number, it is even easier:



                        import itertools
                        

                        
input_list = [3, 30, 34, 5, 9]
                        

                        
answer = max(map("".join, itertools.permutations(map(str, input_list))))
                        

                        
print(answer)





                        share|improve this answer


























                          0














                          The sorted function returns the list in ascending order.



                          But, as you only want the largest number, it is even easier:



                          import itertools
                          

                          
input_list = [3, 30, 34, 5, 9]
                          

                          
answer = max(map("".join, itertools.permutations(map(str, input_list))))
                          

                          
print(answer)





                          share|improve this answer
























                            0












                            0








                            0






                            The sorted function returns the list in ascending order.



                            But, as you only want the largest number, it is even easier:



                            import itertools
                            

                            
input_list = [3, 30, 34, 5, 9]
                            

                            
answer = max(map("".join, itertools.permutations(map(str, input_list))))
                            

                            
print(answer)





                            share|improve this answer












                            The sorted function returns the list in ascending order.



                            But, as you only want the largest number, it is even easier:



                            import itertools
                            

                            
input_list = [3, 30, 34, 5, 9]
                            

                            
answer = max(map("".join, itertools.permutations(map(str, input_list))))
                            

                            
print(answer)






                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered Nov 20 at 8:12









                            Vitor SRG

                            1763




                            1763






























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