ZCW-Arrays-StringArrayUtilities-BlueJ/StringArrayUtils.java

import java.util.*;

/**
 * Created by leon on 1/29/18.
 */
public class StringArrayUtils {
    /**
     * @param array array of String objects
     * @return first element of specified array
     */ // TODO
    public static String getFirstElement(String[] array) {
        return array[0];
    }

    /**
     * @param array array of String objects
     * @return second element in specified array
     */
    public static String getSecondElement(String[] array) {
        return array[1];
    }

    /**
     * @param array array of String objects
     * @return last element in specified array
     */ // TODO
    public static String getLastElement(String[] array) {
        return array[array.length-1];
    }

    /**
     * @param array array of String objects
     * @return second to last element in specified array
     */ // TODO
    public static String getSecondToLastElement(String[] array) {
        return array[array.length - 2];
    }

    /**
     * @param array array of String objects
     * @param value value to check array for
     * @return true if the array contains the specified `value`
     */ // TODO
    public static boolean contains(String[] array, String value) {
        
        for(String x : array) {
            if(value.equals(x)) {
                return true;
            }
        }
        return false;
    }


    /**
     * @param array of String objects
     * @return an array with identical contents in reverse order
     */ // TODO
    public static String[] reverse(String[] array) {
        
        String[] reverseArr = new String[array.length];
        
        for(int i = 0; i < array.length; i++){
            reverseArr[i] = array[array.length - i - 1];
        }
        return reverseArr;
    }

    /**
     * @param array array of String objects
     * @return true if the order of the array is the same backwards and forwards
     */ // TODO
    public static boolean isPalindromic(String[] array) {
        
        String[] reverseArr = reverse(array);
        String[] regArr = new String[array.length];
        
        for(int i= 0; i < array.length; i++){
            regArr[i] = array[i];
                if(regArr[i] == reverseArr[i]) {
                    return true;
                }
            }
        return false;
    }

    /**
     * @param array array of String objects
     * @return true if each letter in the alphabet has been used in the array
     */ // TODO
    public static boolean isPangramic(String[] array) {
        String alphabet = "abcdefghijklmnopqrstuvwxyz";
        String fullCombinedString = String.join("", array).toLowerCase();
        for(char c : alphabet.toCharArray()) {
            if(fullCombinedString.indexOf(c) < 0) {
                return false;
            }
        }
        return true;
        
        
        /*
        for(char c : alphabet.toCharArray()) {
            boolean found = false;
            for(String word : array) {
                word = word.toLowerCase();
                if(word.indexOf(c) >= 0)
                found = true;
                break;
            }
            if(!found) {
                return false;
        }
    }
        return true;*/
    }


    /**
     * @param array array of String objects
     * @param value value to check array for
     * @return number of occurrences the specified `value` has occurred
     */ // TODO
    public static int getNumberOfOccurrences(String[] array, String value) {
        int count = 0;
        for(String s : array) {
            if(s == value) {
                count++;
            }
        }
        return count;
    }

    /**
     * @param array         array of String objects
     * @param valueToRemove value to remove from array
     * @return array with identical contents excluding values of `value`
     */ // TODO
    public static String[] removeValue(String[] array, String valueToRemove) {
        List<String> newArray = new ArrayList<>();
        
        for(String s : array) {
            if(s != valueToRemove) {
                newArray.add(s);
            }
        }
        return newArray.toArray(new String[] {});
    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        List<String> newArray = new ArrayList<>();
        
        for(int i = 0; i < array.length; i++) {
            String added = array[i];
            newArray.add(added);
            int toRemove = 0;
            
            for(; toRemove + i + 1 < array.length; toRemove++) {
                if(array[i + 1 + toRemove] != added){
                    break;
                }                
            }
            i += toRemove;        
        }
        return newArray.toArray(new String[] {});
}

    /**
     * @param array array of chars
     * @return array of Strings with each consecutive duplicate occurrence concatenated as a single string in an array of Strings
     */ // TODO
    public static String[] packConsecutiveDuplicates(String[] array) {
        List<String> newArray = new ArrayList<>();
        
        for(int i = 0; i < array.length; i++) {
            String added = array[i];
            String toAdd = added;
            int toRemove = 0;
            
            for(; toRemove + i + 1 < array.length; toRemove++) {
                if(array[i + 1 + toRemove] != added){
                    break;
                }  
                toAdd += array[i + 1 + toRemove];
            }
            newArray.add(toAdd);
            i += toRemove;        
        }
        System.out.println(Arrays.toString(newArray.toArray()));
        return newArray.toArray(new String[] {});
    }


}