I want to read a String sentence from a Textfield and compare each letter in the String to my list

Question

I want to read a String sentence from a Textfield and compare each letter in the String to my list of already made strings which look like this:

A = 123f;
B = 221d;
H = 2333gg;

And so on..

My question is: how can i read my message as individual strings lets say this is the message: "Hello World"

i want to be able to compare every word to my strings that i have made: so "Hello World" it would compare the first letter "H" and it would make it into what i defined "H" to be, So it would output in a JLabel or anything else as 2333gg .

Thank you in advance!

Answer 1

I think you need to store your letters (A = ..., B = ..., H = ...) into a Map , then you iterate through the input letters (that you can get from the input string using toCharArray() ), and if the Map contains the letter as a key, you output the corresponding value. Something like this:

Map<Character, String> lettersMap = new HashMap<Character, String>();
lettersMap.put(Character.valueOf('A'), "123f");
lettersMap.put(Character.valueOf('B'), "221d");
lettersMap.put(Character.valueOf('H'), "2333gg");

String input = "Hello world";
StringBuffer sb = new StringBuffer();
char[] inputLetters = input.toCharArray();
for (int i = 0; i < inputLetters.length; i++) {
    Character letter = Character.valueOf(inputLetters[i]);
    if (lettersMap.containsKey(letter))
        sb.append(lettersMap.get(letter));
}
System.out.println(sb.toString());

Answer 2

Once you have a String (let's call it myString ), you can iterate through the letters like so:

for (final char c : new StringIterator(myString)) { // Do something with each character (c) }

\n

Does that help?

Edit: I'm SO sorry - I was using a non standard library in a piece of code and forgot.

How about:

for (int i = 0; i < myString.length(); i++)
{
    char c = myString.charAt(i);        
    //Process char
}

Answer 3

You can use String.toCharArray() to get an array of chars, where you can access each char individually.

String[] charArray = userInput.toCharArray();
for (int i = 0; i < charArray.length; i++)
{
    ...
}