Building Utility Class for String Array Objects

• Objective

  • Ensure StringArrayUtilsTest passes each test by completing the methods stubbed out in the class StringArrayUtils
    • String getFirstElement(String[] array)
    • String getSecondElement(String[] array)
    • String getLastElement(String[] array)
    • String getSecondToLastElement(String[] array)
    • boolean contains(String[] array, String value)
    • String[] reverse(String[] array)
    • boolean isPalindromic(String[] array)
    • boolean isPangramic(String[] array)
    • int getNumberOfOccurrences(String[] array, String value)
    • String[] removeValue(String[] array, String value)
    • String[] removeConsecutiveDuplicates(String[] array)
    • String[] packConsecutiveDuplicates(String[] array)

• Purpose

  • To establish greater familiarity with loops and arrays.
  • To demonstrate the implementation of a Utility class
  • And because arrays of Strings are everywhwere in Java. Freakin' Everywhere

String Arrays

Java uses String arrays to store a collection of String values. String arrays are declared and initialized in a similar way to other arrays in Java. Once declared, individual elements of the array can be accessed and manipulated using their index. String arrays are commonly used in Java programs to store and manipulate text data.

You can declare and initialize a String array in Java using the following syntax:

String[] myArray = {"value1", "value2", "value3"};

This creates a String array named myArray with three elements, each initialized with a String value. You can also declare an empty String array and initialize it later:

String[] myArray = new String[3];
myArray[0] = "value1";
myArray[1] = "value2";
myArray[2] = "value3";

This creates an empty String array with three elements, and then initializes each element with a String value.

What did he say about splitting strings into string arrays?

You can split a sentence into a String array in Java using the split() method of the String class. The split() method takes a delimiter as an argument and returns an array of substrings split at each occurrence of the delimiter. Here's an example:

String sentence = "The quick brown fox jumps over the lazy dog";
String[] words = sentence.split(" ");

This splits the sentence string at each space character and stores the resulting substrings in a String array named words. The resulting array will contain the individual words of the sentence as separate elements.

Hmm. That seems important. Maybe I should read it again. Maybe it's really important.

String getFirstElement(String[] array)

• Description
  • Given an array of String objects, return the first element of the array.

Example 1

• Sample Script

  // : Given
  String[] array = {"quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getFirstElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  quick
  

Example 2

• Sample Script

  // : Given
  String[] array = {"brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getFirstElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  brown
  

Example 3

• Sample Script

  // : Given
  String[] array = {"fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getFirstElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  fox
  

String getSecondElement(String[] array)

• Description
  • Given an array of String objects, return the first element of the array.

Example 1

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getSecondElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  quick
  

Example 2

• Sample Script

  // : Given
  String[] array = {"quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};    
  // : When
  String outcome = StringArrayUtils.getFirstElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  brown
  

Example 3

• Sample Script

  // : Given
  String[] array = {"brown", "fox", "jumps", "over", "the", "lazy", "dog"};    
  // : When
  String outcome = StringArrayUtils.getFirstElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  fox
  

String getLastElement(String[] array)

• Description
  • Given an array of String objects, return the last element of the array.

Example 1

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  dog
  

Example 2

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy"};
  
  // : When
  String outcome = StringArrayUtils.getLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  lazy
  

Example 3

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over"};
  
  // : When
  String outcome = StringArrayUtils.getLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  the
  

String getSecondToLastElement(String[] array)

• Description
  • Given an array of String objects, return the next-to-last element of the array.

Example 1

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  String outcome = StringArrayUtils.getSecondToLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  lazy
  

Example 2

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "lazy"};
  
  // : When
  boolean outcome = StringArrayUtils.getNextToLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  over
  

Example 3

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over"};
  
  // : When
  boolean outcome = StringArrayUtils.getNextToLastElement(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  jumps
  

boolean contains(String[] array, String value)

• Description
  • Given an array of String objects named array and a String object named value
    return true if value appears in arrays.

Example 1

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  boolean outcome = StringArrayUtils.contains(array, "the");
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  true
  

Example 2

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  boolean outcome = StringArrayUtils.contains(array, "potatoes");
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  false
  

String[] reverse(String[] array)

• Description
  • Given an array of String objects, return an array with identical contents in reverse order.

Example 1

• Sample Script

  // : Given
  String[] array = {"the", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"};
  
  // : When
  boolean outcome = StringArrayUtils.contains(array, "the");
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  [dog, lazy, the, over, jumps, fox, brown, quick, the]
  

Example 2

• Sample Script

  // : Given
  String[] array = {"Pack", "my", "box", "with", "five", "dozen", "liquor", "jugs"};
  
  // : When
  boolean outcome = StringArrayUtils.contains(array, "potatoes");
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  [jugs, liquor, dozen, five, with, box, my, Pack]
  

Example 3

• Sample Script

  // : Given
  String[] array = {"The", "quick", "onyx", "goblin", "jumps", "over", "the", "lazy", "dwarf"};
  
  // : When
  boolean outcome = StringArrayUtils.contains(array, "potatoes");
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  [dwarf, lazy, the, over, jumps, goblin, onyx, quick, The]
  

boolean isPalindromic(String[] array)

• Description
  • A palindrome is a sequence that is the same backwards and forwards.
  • Given an array of String objects, return true if the array is palindromic.

Example 1

• Sample Script

  // : Given
  String[] array = {"a", "b", "c", "b", "a"}
  
  // : When
  boolean outcome = StringArrayUtils.isPalindrome(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  true
  

Example 2

• Sample Script

  // : Given
  String[] array = {"Is this a plaindrome?", "This is a plaindrome", "Is this a palindrome?"}
  
  // : When
  boolean outcome = StringArrayUtils.isPalindrome(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  true
  

Example 3

• Sample Script

  // : Given
  String[] array = {"Is this a plaindrome?", "This is not a plaindrome", "Is this a palindrome?", "This is not a palindrome"}
  
  // : When
  boolean outcome = StringArrayUtils.isPalindrome(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  false
  

boolean isPangramic(String[] array)

• Description
  • A pangram is a sequence that contains all letters of the alphabet.
  • Given an array of String objects, return true if the array is palindromic.

Example 1

• Sample Script

  // : Given
  String[] array = {"The quick brown", "Fox jumps over", "The lazy dog"}
  
  // : When
  boolean outcome = StringArrayUtils.isPangramic(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  true
  

Example 2

• Sample Script

  // : Given
  String[] array = {"The", "quick", "onyx", "goblin", "jumps", "over", "the", "lazy", "dwarf"};
  
  // : When
  boolean outcome = StringArrayUtils.isPangramic(array);
  
  // : Then
  System.out.println(outcome);
  

• Sample Output

  true
  

int getNumberOfOccurrences(String[] array, String value)

• Description
  • Given an array of String objects named array and a String object named value
    return the number of times value appears in arrays

Example 1

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  int numberOfOccurrences = StringArrayUtils.getNumberOfOccurrences(array, "bba");
  
  // : Then
  System.out.println(numberOfOccurrences);
  

• Sample Output

  4
  

Example 2

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  int numberOfOccurrences = StringArrayUtils.getNumberOfOccurrences(array, "bbb");
  
  // : Then
  System.out.println(numberOfOccurrences);
  

• Sample Output

  2
  

Example 3

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  int numberOfOccurrences = StringArrayUtils.getNumberOfOccurrences(array, "baa");
  
  // : Then
  System.out.println(numberOfOccurrences);
  

• Sample Output

  1
  

String[] removeConsecutiveDuplicates(String[] array)

• Description
  • Given an array of String objects, return an array of Strings with conseuctive duplicates removed.

Example 1

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aba, baa, bab, bba, bbb];
  

Example 2

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "zzz", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aba, baa, bab, bba, zzz, bba, bbb];
  

Example 3

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "zzz", "bba", "bba", "bba", "bbb", "bbb", "aba", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aba, baa, bab, bba, zzz, bba, aba, bbb];
  

String[] packConsecutiveDuplicates(String[] array)

• Description
  • Given an array of char objects, return an array of Strings with consecutive duplicates placed in an array.

Example 1

• Sample Script

  // : Given
  String[] array = {"a", "a", "a", "a", "b", "c", "c", "a", "a", "d"};
  
  // : When
  String[] actual = StringArrayUtils.packConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aaa, b, cc, aa, d, eee];
  

Example 2

• Sample Script

  // : Given
  String[] array = {"t", "t", "q", "a", "a", "a", "b", "c", "c", "a", "a", "d", "e", "e", "e"}; 
  
  // : When
  String[] actual = StringArrayUtils.packConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [tt, q, aaa, b, cc, aa, d, eee];
  

Example 3

• Sample Script

  // : Given
  String[] array = {"m", "o", "o", "n", "m", "a", "n"}
  
  // : When
  String[] actual = StringArrayUtils.packConsecutiveDuplicates(array);
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [m, oo, n, m, a, n];
  

String[] removeValues(String[] array, String valueToRemove)

• Description
  • Given an array of String objects named array and a String object named valueToRemove
    create and return an array containing identical contents excluding objects whose value is equivalent to valueToRemove. Ensure that the length of the newly created array has been resized based on the removal of the undesired elements.

Example 1

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeValues(array, "aba");
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [baa, bab, bba, bba, bba, bba, bbb, bbb};
  

Example 2

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeValues(array, "bba");
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aba, aba, baa, bab, bbb, bbb];
  

Example 3

• Sample Script

  // : Given
  String[] array = {"aba", "aba", "baa", "bab", "bba", "bba", "bba", "bba", "bbb", "bbb"};
  
  // : When
  String[] actual = StringArrayUtils.removeValues(array, "bbb");
  
  // : Then
  System.out.println(Arrays.toString(actual));
  

• Sample Output

  [aba, aba, baa, bab, bba, bba, bba, bba];