Oracle 11G repeats output_put.put_line twice. How to solve this? - string

Question

My loop is given me twice the results. As I only want it one time. What should I do?
for i in 1..length(newStudentNumber) loop
character := SUBSTR(newStudentNumber, i, 1);
newStudentNumber := newStudentNumber || case character
when 'A' then '16'
when 'B' then '17'
when 'C' then '18'
when 'D' then '19'
when 'E' then '20'
when 'F' then '21'
when 'G' then '22'
when 'H' then '23'
when 'I' then '24'
when 'J' then '25'
when 'K' then '26'
when 'L' then '27'
when 'M' then '28'
when 'N' then '29'
when 'O' then '30'
when 'P' then '31'
when 'Q' then '32'
when 'R' then '33'
when 'S' then '34'
when 'T' then '35'
when 'U' then '36'
when 'V' then '37'
when 'W' then '38'
when 'X' then '39'
when 'Y' then '40'
when 'Z' then '41'
else character
end;
end loop;
dbms_output.put_line(newStudentNumber);
I hope I am not too vague with this question
Thanks in advance

Answer 1

Inside your loop you are appending the possibly-converted character to the same string variable you are looping over, newStudentNumber. If you don't want both the old and new value then you need a second variable which you populate in the loop.
-- new variable, which has to be declared
convertedStudentNumber := null;
for i in 1..length(newStudentNumber) loop
character := SUBSTR(newStudentNumber, i, 1);
convertedStudentNumber := convertedStudentNumber || case character
...
else character
end;
end loop;
dbms_output.put_line(convertedStudentNumber);
Now the two variables have different values, one starting TUE..., the other starting 353620....