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Java - Read text file and store it using scanner, gives me empty ArrayList. Split words by using Delimeter

Task is to read an article of text from outside file and put each word (no signs) into and Array List as a separate String.
Although I´m sure my path is correct and readable(I can for example perform character count), no matter what I do my Array List of words from that article comes out as empty. I may be struggling with a way how to separate words from each other and other signs. Also with storing the result of reading.
I´ve been googling for the last 2 hours and reading similar answers here but no success. So decided for the first time to ask a question.
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;
import org.w3c.dom.Text;
public class PlaceForErrors {
public static void main(String[] args) {
Scanner scan = null;
try {
scan = new Scanner(new File("\\Users\\marga\\Desktop\\objekt program\\oo2021\\w05_kontrolltoo1\\textHere.txt")).useDelimiter(" \\$ |[\\r\\n]+");
String token1 = "";
ArrayList<String> text = new ArrayList<String>();
while (scan.hasNext()) {
token1 = scan.next();
text.add(token1);
}
String[] textArray = text.toArray(new String[0]);
for(String element : textArray){
System.out.println(element);
}
//Controlling if the ArrayList is empty and it is
boolean tellme = text.isEmpty();
System.out.println(tellme);
} catch (FileNotFoundException exception) {
System.out.println(exception);
}
finally{
scan.close();
}
}
}

String[] textArray = text.toArray(new String[0]);
This line is your problem. You're trying to allocate the ArrayList into a String array of size 0, resulting in it appearing empty.
I would modify the array declaration to initialize using the ArrayList size, like so:
String[] textArray = text.toArray(new String[text.size()]);
Then you can see if your token delimiter works.

Quick recap of your steps
Your program does a lot. I counted 9 steps:
opens a (text) file as (text) input-stream to read from
create a scanner for tokens from this input-stream using a regular-expression as delimiter (= tokenizer)
scan for and iterate over each subsequent token (if any found) using a while-loop
each of this iteration adds the token to a list
if no more tokens, then iteration ends (or never started!): converts the list to array
loop over each array element using a for-each-loop and print it
check if originally collected list is empty and print true or false
catch the exception if file was not found and print the it
finally close any opened resources: the file that was read from
Now let's start to look for the step where something potentially could go wrong: the places for errors 😏️
Analysis: What can go wrong?
Look at the listed steps above and think of each from a what-could-go-wrong perspective, a quick check list (not correlated to the step-numbers above!):
Can your text-file be found, does it exist and is readable? Yes, otherwise any IOException like FileNotFoundException would have been thrown and printed.
Is the opened file empty with a size of 0 bytes? You can check using:
File textFile = new File("\\Users\\marga\\Desktop\\objekt program\\oo2021\\w05_kontrolltoo1\\textHere.txt");
System.out.println( "File size: " + textFile.length() );
// before passing the extracted file-variable to scanner
scan = new Scanner( textFile ).useDelimiter(" \\$ |[\\r\\n]+");
Does the delimiter/regex properly split/tokenize an example input string? Try:
// Just a separate test: same delimiter, with test-input
String delimiterRegex = " \\$ |[\\r\\n]+";
String testInput = " $ Hello\r\nWorld !\n\nBye.";
// so we create a new scanner
Scanner testScanner = new Scanner( testInput ).useDelimiter(delimiterRegex);
int tokenCount = 0;
while( testScanner.hasNext() ) {
tokenCount++;
System.out.println("Token " + tokenCount + ": " + testScanner.next() );
}
testScanner.close();
Should print 3 tokens (Hello, World !, Bye.) on 3 lines in console. The special sequence $ (space-dollar-space), any \n or \r (newline or carriage-return) are omitted and have split the tokens.
We should check the list directly after the while-loop:
// Not only checking if the ArrayList is empty, but its size (is 0 if empty)
System.out.println("Scanned tokens in list: " + text.size());
If it is empty, then we neither need to fill the array, nor loop to print will start (because nothing to loop).
Hope these explanations help you to perform the analysis (debugging/testing) yourself.
Let me know if it helped you to catch the issue.
Takeaway: Divide and conquer!
Why did I count the steps, above? Because all are potential places for errors.
In developer jargon we also say this main method of class PlaceForErrors has many responsibilities: counted 9.
And there is a golden principle called Single Responsibility Principle (SRP).
Put simply: It is always good to split a large problem or program (here: your large main method) into smaller pieces. These smaller pieces are easier to work with (mentally), easier to test, easier to debug if errors or unexpected happens. Divide & conquer!
If it works, start improving
You can split up this long method doing 9 steps into smaller methods.
Benefit: each method can be tested in isolation, like the testScanner.
If your program finally works as expected and your manual test went green.
Then you should post the working code to the sister-site: CodeReview.
Be curious and ask again, e.g. how to split up the methods, how to make testable, etc.
You'll get lot's of experienced advise on how to improve it even more.

Thank you for your input everyone!
Regarding the code, I went and checked everything step by step and on the way learned more about delimiters and scanner. I fixed my delimiter and everything worked just fine now.
Beside the fact that I made a newbie mistake and didn´t show the full code, as I though it would take away the attention from the main problem. I had two conflicting scanners in my main function(one I showed you and the other one was scanning again and counting letters A). And they both worked great separately(when one or the other is commented out), but refused to work together. So I found a way to combine them and use scanner only once. I will share my full code for reference now.
I learned my mistake, and will provide the my full code always in the future.
If someone is curious the full task was the following:
Read the text from a separate file using scanner and store it in an Array List.
Count how many letters "A" (small or big) there were and how big of % they made out of all the letters in the text.
Count how many words had one letter A, two letters A in them, etc.
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;
public class Trying {
public static void main(String[] args) {
Scanner scan = null;
try {
//SCANNING FILE AND CREATING AN ARRAYLIST
scan = new Scanner(new File("\\Users\\marga\\Desktop\\objekt program\\oo2021\\w05_kontrolltoo1\\textHere.txt")).useDelimiter("[.,:;()?!\"\\s]+");
int aCount = 0;
int letterCount =0;
String token1 = "";
int wordWithAtLeastOneA = 0;
int wordWithA = 0;
int word1A = 0;
int word2A = 0;
int word3A = 0;
int word4OrMoreA = 0;
ArrayList<String> text = new ArrayList<String>();
// SCANNING EVERY WORD INTO AN ARRAY LIST
while(scan.hasNext()){
token1 = scan.next();
text.add(token1);
}
System.out.println("Amount of words in the scanned list is : " + text.size());
//COUNTING HOW MANY LETTERS 'A' TEXT HAS
for(String element : text){
for (int i=0;i<=element.length()-1;i++){
if (element.charAt(i) == 'A' || element.charAt(i) == 'a') {
aCount++;
}
}
}
System.out.println("There are "+aCount+" letters 'A'. ");
//HOW MANY LETTERS IN TOTAL TEXT HAS
for(String element : text){
for (int i=0;i<=element.length()-1;i++){
letterCount++;
}
}
//COUNTING HOW MANY WORDS HAVE 'A' LETTER IN THEM
for(String element : text){
for (int i=0;i<=element.length()-1;i++){
if (element.charAt(i) == 'A' || element.charAt(i) == 'a') {
wordWithAtLeastOneA++;;
break;
}
}
}
System.out.println("There are "+wordWithAtLeastOneA+" words that have at least one letter 'A' in them.");
System.out.println();
//COUNTING NUMBER OF WORDS THAT HAVE 1/2/3 or more 'A' LETTER IN THEM
for(String element : text){
wordWithA = 0;
for (int i=0;i<=element.length()-1;i++){
if (element.charAt(i) == 'A' || element.charAt(i) == 'a') {
wordWithA++;
if(wordWithA == 1){
word1A++;
}else if (wordWithA == 2){
word2A++;
}else if (wordWithA == 3){
word3A++;
}else if (wordWithA >= 4){
word4OrMoreA++;
}
}
}
}
System.out.println("There were "+ word1A+ " words, that had one letter 'A' in them." );
System.out.println("There were "+ word2A+ " words, that had two letters 'A' in them." );
System.out.println("There were "+ word3A+ " words, that had three letters 'A' in them." );
System.out.println("There were "+ word4OrMoreA+ " words, that had 4 or more letters 'A' in them." );
//COUNTING HOW MANY LETTERS THERE ARE IN TOTAL, COMPARE TO NUMBER OF "A" LETTERS
int percentOfA = aCount*100/letterCount;
System.out.println();
System.out.println("The entire number of letters is "+ letterCount+" and letter 'A' makes " + percentOfA+ "% out of them or " +aCount+ " letters.");
// for(String element : textArray){
// System.out.println(element);
// }
} catch (FileNotFoundException exception) {
System.out.println(exception);
}
finally{
scan.close();
}
}
}
And the text is:
Computer programming is an enormously flexible tool that you can use to do amazing things that are otherwise either manual and laborsome or are just impossible.
If you are using a smartphone, a chat app or if you are unlocking your car with the push of a button,
then you must know that all these things are using some kind of programming.
You are already immersed in the programs of different types.
In fact, software is running your life. What if you learn and start running these programs according to your will?
And the output is:
There are 35 words that have at least one letter 'A' in them.
There were 35 words, that had one letter 'A' in them.
There were 3 words, that had two letters 'A' in them.
There were 0 words, that had three letters 'A' in them.
There were 0 words, that had 4 or more letters 'A' in them.
The entire number of letters is 416 and letter 'A' makes 9% out of them or 38 letters.

How would I separate a sentence into individual words with a loop and send them individually into an ArrayList in Java?

I have a very specific problem for my CS course. I have a sentence in a string, and I need that separated into individual words within an ArrayList, and cannot use the split method.
The issue I have is that I have had zero teaching on arrays, only the bare minimum teaching for loops and String statements. I've done a lot of research and figured out the best way to go about making the loop, and sending the words to the ArrayList, however I still can't find a good way to actually have it loop through the sentence and separate each individual word at all. I get how easily it can be done to separate the very first word, however after that I get lost. I have no idea how to make the loop for its other iterations specifically grab the next word in the sentence after the one it previously got.
(Note: The only utilities imported are Scanner, File, HashMap, ArrayList, Random, and *)
What I'm looking for is any tips of specific methods I should try and employ or research. Or perhaps a set of code that is fairly functional in doing something similar to what I'm looking for that I can look at and build my own code off of.

When you said the word "word"(That's weird) I assume that they are separated by spaces. If you are reading in the inputs, then just use Scanner... Then:
Scanner input = new Scanner(System.in);
ArrayList<String> words = new ArrayList<String>();
for(int i = 0;i<numberOfWord;i++){
words.add(input.next());// .next() method read data that are separated by space
}
or:
String theLineOfWord;//Given to you
StringTokenizer st = new StringTokenizer(theLinOfWord);//Used to separate words.
ArrayList<String> words = new ArrayList<String>();
while(st.hasMoreTokens()){
words.add(st.nextToken();
}
or:
public static ArrayList<String> getWords(String line){
ArrayList<String> words = new ArrayList<String>();
line += " ";//add a space to ignore the ending case
while(line.length() != 0) {
words.add(line.substring(0, line.indexOf(' ')));//add the word to the list
line = line.substring(line.indexOf(' ') + 1, line.length());//take out the useless string away
}
return words;
}

Check if user input strings contain the same letters

How can I check if strings put in by the user via scanner (the user can choose how many words he wants to type in) contain the same letters? Lets say the users types in the following 3 words:
race
bicycle
computer
Every word in this example contains 'e' and 'c'. How can I compare those strings and safe the result (e and c) in a new string?
public class Comparison {
public static void main(String[] args) {
String letters = "";
Scanner input = new Scanner(System.in);
System.out.println("How many words do you want to type in?:");
count = input.nextInt();
String[] words= new String[count];
for (int i = 0; i < words.length; i++) {
if (words[i].charAt(0) == words[j].charAt(0)) {
letters = letters + words[i].charAt(j);
}
}
}

There are several pieces needed here.
Get the words from the user with a scanner. You are not asking about that. The idea would be to prompt, read in the input, and generate an array of strings. One way to do that might be to use the split method. You were not asking about this part. You asked what to do with this string array once you had it. To test the other parts you could use args passed to main, then develop this piece.
A method to find the common letters between just two strings. You indicated that you had such a method working. So I am not going to share that. Let's just imagine it looked like:
/**
Method findCommonLetters
*
#param word1 first word
#param word2 second word
#return a string containing the common letters in the two words, no repeats
*/
public String findCommonLetters(String word1, String word2) {
//your code here
}
A way to take an arbitrary length array of strings and get the letters all have in common. That is what you were asking for. Here is a method that will do that assuming you have the method described in 2 working. The idea is to work through just 2 at a time and look for only those letters in common in all the words so far in the next word (and loop until we have processed all the words). Code follows:
/**
Method findCommonLetters
*
#param words An array of words
#return A String containing the letters to all the words
*/
public String findCommonLetters(String[] words)
{
if (words.length == 0) {
return ""; //there are no letters
} else if (words.length == 1) {
//if the desired behavior is as I do here, this else if block could go away
return words[0]; //trivially all the words have the same letters
} else {
String result = words[0]; // first word
for (int i = 1; i < words.length; i++) {
result = findCommonLetters(result, words[i]); //find letters in common between all words processed so far and next word
//if you want, you could break here if result is empty
}
return result;
}
}
Putting together these three pieces will give the desired result.

Trying to create an Acronym out of user input

Hello I am working on an assignment and I'm running into issues I was hoping for a little direction...
The purpose is to have user input a phrase and create an acronym out of that phrase. Anything over three words will be ignored.
I'm having issues with the acronym part, I am able to get the first character and figured that I would loop through the user input and grab the character after a space, but that is not working. All I am getting is the first character, which is obvious because I grab that first, but I can't figure out how to "save" the other two characters. Any help is greatly appreciated.
*********UPDATE************************
So thanks to an answer below I have made progress with using the StringBuilder. But, now if I enter "Your Three Words" the Output is: YYYYYTYYYYYWYYYY
Which is progress but I can't understand why it's repeating those first characters so many times??
I edited the code too.
*********UPDATE*****************************
public class ThreeLetterAcronym {
public static void main(String[] args) {
String threeWords;
StringBuilder acronym = new StringBuilder();
Scanner scan = new Scanner(System.in);
System.out.println("Enter your three words: ");
threeWords = scan.nextLine();
for(int count = 0; count < threeWords.length(); count++) {
acronym.append(threeWords.charAt(0));
if(threeWords.charAt(count) == ' ') {
++count;
acronym.append(threeWords.charAt(count));
}
}
System.out.println("The acronym of the three words you entered is: " + acronym);
}
}

You can't save the other characters because char is supposed to store only one character.
You can use a StringBuilder in this case
StringBuilder acronym = new StringBuilder();
Then in your loop simply replace it with
String[] threeWordsArray = threeWords.split(" ");
for(String word : threeWordsArray) {
acronym.append( word.substring(0, 1) );
}
**updated

You store the character at the current index in space:
char space = threeWords.charAt(count);
Then you compare the value of space with the integer value 3:
if(space < 3)
This will almost certainly never be true. You are asking for the numeric value of a character. Assuming it is a letter it will be at least 65. I suspect that your intention is to store something different in the variable space.

Compare two Lists for Anagrams - Java

I'm currently working on an anagram solver. I saw a really good post which had one recommendation on alphabetizing the letters of both the user input and dictionary list before comparing. It seemed interesting so I'm giving it a try. Previously I used permutations, but I want something that I can eventually (and efficiently) use to solve multi word anagrams.
I can put both my user input and dictionary into char arrays and sorting alphabetically. Now I need to compare each so I can determine if something is an anagram or not. I thought about taking the alphabetized user input and determining if the alphabetized dictionary contained it or not. I've posted my code below. As you can guess I'm a little confused on the logic of this process. I was wondering if someone could help me straighten out the logic a little. Thanks for any help.
public class AnagramSolver1 {
public static void main(String[] args) throws IOException {
List<String> dictionary = new ArrayList<String>();
List<String> inputList = new ArrayList<String>();
BufferedReader in = new BufferedReader(new FileReader("src/dictionary.txt"));
String line = null;
Scanner scan = new Scanner(System.in);
while (null!=(line=in.readLine())){
dictionary.add(line);
}
in.close();
char[] sortDictionary;
char[] inputSort;
System.out.println("Enter Word: ");
String input = scan.next();
inputList.add(input);
//Getting a little confused here. I thought about sorting my input
//then iterating through my dictionary (while sorting it too) and comparing
//thus far it produces nothing
for(int i = 0; i < inputList.size(); i++){
inputSort = inputList.get(i).toCharArray();
Arrays.sort(inputSort);
for (int j = 0; j < dictionary.size(); j++) {
sortDictionary = dictionary.get(i).toCharArray();
Arrays.sort(sortDictionary);
if(inputSort.equals(sortDictionary)){
System.out.println("Anagram" +dictionary.get(i));
} //end if
}//end for
}//end for
}//end main
}

Why not maintain a Map<String, Set<String>> that maps a sorted-character string to a set of strings that are its anagrams. You can update this map as you read words from the dictionary. For example, if you read the word dog you would add an entry to the map "dgo" => {"dog"} (notice that dgo consists of the sorted characters of the word dog). Then if you read the word god, you would sort its characters to obtain the same dgo and consequently amend the previous entry to be "dgo" => {"dog", "god"}. You would of course repeat this for every word in the dictionary.
This should allow for quick and easy querying. If you wanted to then find anagrams of the word dog you would use map.get(sortChars("dog")).
On another note, I'm going to reiterate what the other answer mentioned, namely that it's important to modularize your code. You should put logically related functions/tasks in their own methods as opposed to having everything in one place. This helps with readability and your/others' ability to maintain your code in the future.

You are doing too many things at once here. You've got file IO, user input, sorting and the algorithm all in one place. Try to modularize it so you have a function called isAnagram(List<Character> firstPhrase, List<Character> secondPhrase). Make sure that works correctly, then have all the other steps figure out how to call it. This way you can test your algorithm without requiring user input. This will be a much faster feedback loop.
It's algorithm will work like this:
(optionally) copy the contents of the input so you don't mutate the input
compare their lengths. If they're not equal, return false
sort each list
iterate element by element and check if they're equal. If they're not, return false
if you reach the end, return true.