Assign Characters to a substring

Programming Questions

dauwak

Assign Characters to a substring

in Programming Questions • 1 year ago

Hi, I should want to assign a letter to a substring in a String,

for example, with two string:

String KeyList = "abcdefghilmnopqrstuvzABCDEFGHILMNOPQRSTUVZ";
String[] RecordList = { "example", "B", "C",};

I want record a substring to compose a word recorded in an index of the string RecordList:

RecordList[0].substring(0,1) = KeyList.charAt(x);

The full code I use is:

PFont AndaleMono;

void setup() {
size(800, 600);
smooth();
stroke(200);
background(255);
AndaleMono = loadFont("AndaleMono-11.vlw");
fill(230);
rect(50,35,200,20);
}

void draw() {
smooth();

}

String KeyList = "abcdefghilmnopqrstuvzABCDEFGHILMNOPQRSTUVZ";
String[] RecordList = {
"example",
"B",
"C",
};

void keyPressed() {

for (int x = 0; x < 42; x++) {
if (key == KeyList.charAt(x)) {
    textFont(AndaleMono,11);
    fill(50);
    textAlign(LEFT);
    text(KeyList.charAt(x),52,50);
    RecordList[0].substring(0,1) = KeyList.charAt(x);

} else {

}
}
}

This code give me an error "The left-hand side of an assignment must be a variable". What the problem? Or how could I record a substring of a string in another string?

Thank you so much for answering...

Replies(2)

PhiLho

Re: Assign Characters to a substring

1 year ago

Strings in Java are immutable: you cannot change them in place, unlike C strings.
You create a new string and replace the old one with the new one.
Or you use another structure, which can be converted to a string later, like an array of chars, or StringBuilder.

dr.mo

Re: Assign Characters to a substring

1 year ago

i am not sure what your record list is supposed to do as currently you are always trying to replace the first character in the first string. in that chase you might as well just store that in a single char.

or if you need to store a list you could as already suggested use a char array.

perhaps like this

String KeyList = "abcdefghilmnopqrstuvzABCDEFGHILMNOPQRSTUVZ";

//you could use a dynamic list here (eg ArrayList) but that is overkill, just make sure charList //this big enough:

char[] charList = new char[1000];

int count = 0; //keep track of the index that we are storing the next character into

void keyPressed()

{

   for (int x = 0; x < KeyList.length(); x++) // don't use fixed sizes - better to use string.length()

   {
             if (key == KeyList.charAt(x))

           {

if(count < charList.length)

{

            charList[count++] = KeyList.charAt(x);

                 }

//else list is full - either use bigger list or do something else.

      }

      }
}

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