CC-2 : Filter input list of Strings / Search Directory file names by range.

Description:

Given a String array, sort the same alphabetically and then filter the Strings between range of two input Strings and return the result.

Test cases and expected outputs:

Input Parameters	Expected outputs
arr1={ "Archie", "Arthur", "Charlie", "Edward", "Freddie", "Noah", "Oliver", "Henry", "Avery", "Leo", "Teddy", "Thomas", "Stephen", "Wallace", "Louis", "Paul", "Logan", "Sonny", "Wilfred"}; Sort above alphabetically and return range of names between “Charlie” (inclusive) and “Teddy” (exclusive).	Charlie, Edward, Freddie, Henry, Leo, Logan, Louis, Noah, Oliver, Paul, Sonny, Stephen
arr1={ "Archie", "Arthur", "Charlie", "Edward", "Freddie", "Noah", "Oliver", "Henry", "Avery", "Leo", "Teddy", "Thomas", "Stephen", "Wallace", "Louis", "Paul", "Logan", "Sonny", "Wilfred"}; Sort above alphabetically and return range of names between “Edward” (Inclusive) and “Leo” (exclusive).	Edward, Freddie, Henry

Pseudocode:

The java method should accept following input parameters: arr (String array), from (start of filter range, inclusive), to(end of filter range, exclusive).

Initialize a variable tSet of type TreeSet to hold the input elements.

Using a for loop iterate through arr, using idx as a loop variable with initial value 0 and increment idx till it reaches arr.length-1:

Add arr[idx] to tSet.

At completion of above loop, tSet contains all the unique Strings in arr alphabetically sorted, as TreeSet automatically sorts input elements in their natural order.

Use an iterator to access elements from tSet and add the same to String array named retVal. Return retVal.

Code:

public String[] setSearchDirectory(String[] arr, String from, String to) {
	TreeSet<String> tSet=new TreeSet<String>();
	for (int idx=0; idx <arr.length; idx++) {
		tSet.add(arr[idx]);
	}
	TreeSet subSet=(TreeSet) tSet.subSet(from, to);
	String retVal[]=new String[subSet.size()];
	int idx=0;
	Iterator<String> itr=subSet.iterator();
	while (itr.hasNext()) {
		retVal[idx]=itr.next().toString();
		idx++;
	}
	return retVal;
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

import java.util.Iterator;
import java.util.TreeSet;

public class SetSearchDirectory{
	
public String[] setSearchDirectory(String[] arr, String from, String to) {
	TreeSet<String> tSet=new TreeSet<String>();
	for (int idx=0; idx <arr.length; idx++) {
		tSet.add(arr[idx]);
	}
	TreeSet subSet=(TreeSet) tSet.subSet(from, to);
	String retVal[]=new String[subSet.size()];
	int idx=0;
	Iterator<String> itr=subSet.iterator();
	while (itr.hasNext()) {
		retVal[idx]=itr.next().toString();
		idx++;
	}
	return retVal;
}

	
public static void main(String[] args) {
	SetSearchDirectory sp=new SetSearchDirectory();
	String[] retVal;
	try {
	String[] arr1={ "Archie", "Arthur", "Charlie", "Edward", "Freddie", "Noah", "Oliver", "Henry", "Avery", "Leo", "Teddy", "Thomas", "Stephen", "Wallace", "Louis", "Paul", "Logan", "Sonny", "Wilfred"};
	printArraySummary(arr1, "Original Array");
	System.out.println("Names From "+ "Charlie"+ " to "+ "Teddy");
	retVal=sp.setSearchDirectory(arr1, "Charlie", "Teddy");
	printArraySummary(retVal, "Searched Elements");
			
	System.out.println("Names From "+ "Edward"+ " to "+ "Leo");
	retVal=sp.setSearchDirectory(arr1, "Edward", "Leo");
	printArraySummary(retVal, "Searched Elements");
		
			
	}catch (Exception exception) {
	System.out.print("Exception,"+ exception);
	exception.printStackTrace();
				
	}
}
			
public static void printArraySummary(String[] intArray, String label) throws Exception {
   	// Case 1: The input Array is null !!
	if (intArray == null) { System.out.println("\n\n Input Array was null !! \n"); return; }
	// Case 2: Print input Array by index (first to last)
	System.out.println();
	System.out.println("************************************************************************");
	System.out.print(label+" : ");
	int arrayIndex=0;
	for (arrayIndex=0; arrayIndex< intArray.length; arrayIndex++) {
			System.out.print(intArray[arrayIndex]);
			if (arrayIndex< intArray.length-1) {System.out.print(",");}
	} 
	System.out.println();
	System.out.println("*************************************************************************");
	System.out.println();
	Thread.sleep(2000);
	return;
}				

}