Equality between a String value and an array value

Question

So this is a portion of my code. If i entered " 1111 " for the preTranslation String, it should print out true but it prints out false. I'm guessing that .equal() cannot compare the two values but I don't know another way. Any help?

import javax.swing.JOptionPane;
import java.util.Arrays;

public class test3
{
    public static void main ( String [] args )
    {

    String s1 = "Morse";

    // Decide whether Morse code or English
    String decide = JOptionPane.showInputDialog("Enter 'English' for Morse to English code translation and 'Morse' for English to Morse code translation. Pay attention to Caps.");

    // Enter String & decide whether to convert to Morse or English
    String preTranslation = JOptionPane.showInputDialog("Enter the words you wish to translate.");

    if ( decide.equals( s1 ))
        toMorse( preTranslation );

    else
        toEnglish( preTranslation );
    }

// Translate to Morse
public static void toMorse( String preTrans )
{
    // Initialize english letters
    char[] english = new char[3];


    // Initialize english numbers
    english[0] = 1;
    english[1] = 2;
    english[2] = 3;

    // Initialize morse characters
    String[] morse = {".","-", ".-"};

    // Replace spaces with |
    String phraseWithDelimiter = preTrans.replace( " ", "|");

    String[] translation = new String[phraseWithDelimiter.length()];
    System.out.println( phraseWithDelimiter.substring(0, 1).equals( english[0] )); // Should print out to be true
    }
}

just a comment here, why don't you do a toLower() on the "decide" String (and compare it against ("morse") so you don't have to tell users to "Pay attention to Caps". Just a thought! — Sam Dozor
– Sam Dozor, Commented Aug 22, 2012 at 23:12

JamesB · Accepted Answer · 2012-08-22 23:08:46Z

2

You are comparing a String object with a character (a char) so equals will always return false. If you want to get a single character from a string, use charAt method instead of substring.

answered Aug 22, 2012 at 23:08

JamesB

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Comments

Sujith Surendranathan · Accepted Answer · 2012-08-22 23:12:09Z

0

Use String.valueOf(phraseWithDelimiter.substring(0, 1)).equals( english[0] ));

answered Aug 22, 2012 at 23:12

Sujith Surendranathan

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Reimeus · Accepted Answer · 2012-08-22 23:18:55Z

0

Using charAt to correct for character comparison:

phraseWithDelimiter.charAt(0) == english[0]

You define :

english[0] = 1;

which is ASCII 1, a character which cannot be entered by the user. You need to define:

english[0] = '1';

answered Aug 22, 2012 at 23:18

Reimeus

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Comments

amor214 · Accepted Answer · 2012-08-22 23:19:42Z

Just to elaborate on JamesB's answer, if you would look at the implementation of the equals method of the String class:

public boolean equals(Object anObject) {
    if (this == anObject) {
        return true;
    }
    if (anObject instanceof String) {
        String anotherString = (String) anObject;
        int n = value.length;
        if (n == anotherString.value.length) {
            char v1[] = value;
            char v2[] = anotherString.value;
            int i = 0;
            while (n-- != 0) {
                if (v1[i] != v2[i])
                        return false;
                i++;
            }
            return true;
        }
    }
    return false;
}

You would notice that if the object you're comparing to is not an instance of a String (which in your example is a character), it immediately returns false. :)

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