Sorting of name with upper case and lower case wise

Sorting names such that uppercase names appear first and are sorted alphabetically, followed by lowercase names sorted alphabetically, can be achieved by assigning weights or using a mathematical formula to prioritize uppercase over lowercase.

Here’s an approach:

Math-based Formula

You can use ASCII values to determine the sort order:

ASCII values of uppercase letters (A-Z) range from 65 to 90.
ASCII values of lowercase letters (a-z) range from 97 to 122.

To sort:

Ø Calculate a "weight" for each string:

ü For uppercase names, use a smaller weight (e.g., 1).

ü For lowercase names, use a larger weight (e.g., 2).

Ø Then sort based on this weight and alphabetically within groups.

Example Code

java

import java.util.*;

public class SortNames {

public static void main(String[] args) {

List<String> names = Arrays.asList("alice", "Bob", "charlie", "ALAN", "BOB", "david", "Amy");

// Sort names: Uppercase first, then lowercase

List<String> sortedNames = names.stream()

.sorted((name1, name2) -> {

// Calculate weights: 1 for uppercase, 2 for lowercase

int weight1 = Character.isUpperCase(name1.charAt(0)) ? 1 : 2;

int weight2 = Character.isUpperCase(name2.charAt(0)) ? 1 : 2;

// Compare weights first

if (weight1 != weight2) {

return Integer.compare(weight1, weight2);

}

// If weights are equal, compare names alphabetically

return name1.compareTo(name2);

})

.toList();

System.out.println("Sorted names: " + sortedNames);

}

Explanation

Weight Calculation:

Ø Use Character.isUpperCase to check if the first character of the name is uppercase.

Ø Assign 1 to uppercase names and 2 to lowercase names.

Sorting Logic:

Ø Sort by weights first (Integer.compare(weight1, weight2)).

Ø For names with equal weights, use name1.compareTo(name2) to sort alphabetically.

Output

For the input list:

text

["alice", "Bob", "charlie", "ALAN", "BOB", "david", "Amy"]

The output will be:

Text

[ALAN, Amy, BOB, Bob, alice, charlie, david]

Why Math-Based?

The Character.isUpperCase method effectively distinguishes between uppercase and lowercase based on ASCII ranges, and the sort order is influenced mathematically by assigning weights.

You can further customize the formula if specific patterns or additional priorities are needed.

Second Approach:

To sort a list in Java such that uppercase elements appear first in sorted order followed by lowercase elements also in sorted order, you can use a custom comparator. Here’s how you can achieve this:

Sort by Case: Ensure uppercase elements come before lowercase elements.
Sort Alphabetically: Sort elements alphabetically within their case group.

Java Code Implementation

Here's how you can implement the custom sorting logic:

java

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class CustomSort {

// Custom comparator to sort by case and then alphabetically

public static Comparator<String> customComparator() {

return (s1, s2) -> {

boolean s1UpperCase = Character.isUpperCase(s1.charAt(0));

boolean s2UpperCase = Character.isUpperCase(s2.charAt(0));

if (s1UpperCase && !s2UpperCase) {

return -1;

} else if (!s1UpperCase && s2UpperCase) {

return 1;

} else {

return s1.compareTo(s2);

}

};

}

public static void main(String[] args) {

List<String> list = new ArrayList<>();

list.add("apple");

list.add("Banana");

list.add("cherry");

list.add("Apricot");

list.add("banana");

list.add("Cherry");

list.add("apricot");

// Sort the list using the custom comparator

Collections.sort(list, customComparator());

// Print the sorted list

for (String s : list) {

System.out.println(s);

}

Explanation

Custom Comparator: The customComparator method returns a Comparator<String> that:

Ø Checks the case of the first character of the strings.

Ø If one string is uppercase and the other is lowercase, it ensures the uppercase string comes first.

Ø If both strings are of the same case, it sorts them alphabetically.

Main Method:

Ø Creates a list of strings.

Ø Sorts the list using Collections.sort with the custom comparator.

Ø Prints the sorted list.

Output

For the provided list, the sorted output will be:

Apricot

Banana

Cherry

apple

apricot

banana

cherry

Conclusion

This program demonstrates how to sort a list in Java such that uppercase elements appear first, followed by lowercase elements, with each group sorted alphabetically. Adjust the list in the main method to test with different inputs.