php make all the strings in an array uppercase code example

Example 1: javascript convert in a string the items of an array

const arr = [1, 2, 'a', '1a'];
const str = arr.toString();
console.log(str); //> "1,2,a,1a"

Example 2: loop and save letters in a string java

StringBuilder phone = new StringBuilder();
for (int i = 0; i < number.length(); i++){
    if (Character.isLetter(number.charAt(i))){
        phone.append(getNumber(Character.toUpperCase(number.charAt(i))));
    }else{
        phone.append(number.charAt(i));
    }
}

System.out.println("Your number is " + phone.toString());