Separate each number with semicolon(;) in Java

Question

In a text box that has the variable name MMdados I put the numbers: 0;1;0

Then I created a variable String recebeMM who receives MMdados.getText();

I send these numbers to a text field that has the variable name MM causing these numbers to be below each other.

Ends up printing like this:

0
;
1
;
0

My problem is that the ; You have to separate the numbers and not show up and you can’t count the size of the recebeMM.length() in the for.

Code:

private void BenviarActionPerformed(java.awt.event.ActionEvent evt) {                                        

    String recebeMM;

    recebeMM = MMdados.getText();

    String texto = "";

    recebeMM.split ("[;]");

    for(int i = 0; i < recebeMM.length(); i++){


        if(recebeMM != " "){ 


            texto = texto + recebeMM.charAt(i) + "\n";

        }

        MM.setText(texto);
    }

}

I used the recebeMM.split ("[;]");. But it didn’t work.

Answer 1

split even receives a regular expression and yours is not wrong, since [] combines a single character of contained in [], for example to [abc] will match only a, b, or c. In your case it doesn’t matter ; or [;].

Assuming you need it, from the entrance 0;1;0, of a result like this:

0
1
0

Your problem is basically in the way you are recovering values after the split. This method returns a character array, so you need to assign this result to any variable, for example as follows:

final String[] values = recebeMM.split("[;]");

After this, in the for, instead of iterating the characters of recebeMM we will iterate the result vector of split. We can use a enhaced for , something like this:

for (final String value : values) {
    if (value.trim().length() > 0) {
        texto.append(value);
        texto.append("\n\r");
    }
}

Or the for pattern, something like that:

for (int i = 0; i < values.length; i ++) {
    final String value = values[i];
    if (value.trim().length() > 0) {
        texto.append(value);
        texto.append("\n\r");
    }
}

Note also this excerpt:

if(recebeMM != " ")

Well, this will always be true, since recebeMM is 0;1;0, then the only thing you’re doing is picking up character by character, including a \n between them and informing as text of MM.

A way to use the charAt how you used it would be more or less this, so we wouldn’t need the split:

final int length = recebeMM.length();
for (int i = 0; i < length; i++) {
    final char value = recebeMM.charAt(i);
    if (value != ' ' && value != ';') {
        texto.append(value);
        texto.append("\n\r");
    }
}

Another thing is that you must do the car return, using \r when assigning the value to a JTextField, for example, otherwise the result will be something like 0 1 0 by making a MM.getText(). For this, just use \n\r in place of only \n.

Finally a tip: always consider using StringBuilder (or even StringBuffer, depending on the context) rather than concatenate strings.

A version for your method BenviarActionPerformed would be this:

private void BenviarActionPerformed(final java.awt.event.ActionEvent evt) {
    final String recebeMM = MMdados.getText();

    final StringBuilder texto = new StringBuilder();
    final String[] values = recebeMM.split("[;]");

    for (final String value : values) {
        if (value.trim().length() > 0) {
            texto.append(value);
            texto.append("\n\r");
        }
    }

    MM.setText(texto.toString());
}

Answer 2

You have any array: list

Just do:

String myJoinedString = Joiner.on(";").join(list);

This code "joins" the elements of your list with the separator ;

EDIT: With this code, Joiner does not "leave" a separator at the end, and can be replaced by line break or anything else needed in place of the ;