Custom comparison for integer strings

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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)

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)

How to create a custom comparator to sort a numbering system , Advantage of this approach is that you will not have to parse your String to int each time you want to compare two strings (which can be costly), but you will be  Custom numeric format strings are also supported by the .NET composite formatting feature, which is used by some Write and WriteLine methods of the Console and StreamWriter classes, the String.Format method, and the StringBuilder.AppendFormat method.

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)

Java, Below example illustrate the use of == for string comparison in Java: In java Comparable interface compares values and returns an int, these int values may feature of Collator class is the ability to define our own custom comparison rules. The comparison in the method is different depending on the data type of the value that is being compared. String.Compare is used in this example because the property that is chosen for the comparison is a string. IComparer The role of IComparer is to provide additional comparison mechanisms. For example, you may want to provide ordering of your class on several fields or properties, ascending and descending order on the same field, or both.

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)

5 ways to Compare String Objects in Java, The compare() method allows you to compare String on any custom order, compareTo(groovy); // negative integer because groovy comes before java in  Note that the test for equality with String.Equals and the == and != operators differs from string comparison using the String.CompareTo and Compare(String, String) methods. While the tests for equality perform a case-sensitive ordinal comparison, the comparison methods perform a case-sensitive, culture-sensitive comparison using the current

Sort using a custom comparator, Quick sort array function with custom comparison function ---# PROC quicksort OP LENGTH = (STRING a)INT: ( UPB a + 1 ) - LWB a; An integer is a variable that specifically holds a numerical value. Whereas a string is a variable that can hold a range of characters (including numbers). Strings are usually enclosed in inverted commas like so: "This is a string."

Java ArrayList of Object Sort Example (Comparable And Comparator), If you are looking for sorting a simple ArrayList of String or Integer then you can However if the ArrayList is of custom object type then in such case you have  If the random number generator is of type integer, optionally a seed parameter and a maximum number may be provided. An optional string format parameter allows the output to be formatted using it, and an optional base64 parameter specifies whether the output is base64 encoded randomGeneratorType [guid, integer] outputClaim (String).

IComparer.Compare(Object, Object) Method (System.Collections , The following example uses the IComparer interface to sort a string array. In this example, the Compare Compare with the parameters reversed. int IComparer. Examples. The following example demonstrates the Sort(Int32, Int32, IComparer<T>) method overload and the BinarySearch(Int32, Int32, T, IComparer<T>) method overload.. The example defines an alternative comparer for strings named DinoCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface.

Comments
  • Because sorted returns a new list.