If the input is a1bc2def3 output should be abcbcdefdef - arrays

Question

If the given input is a1bc2def3 then output should be abcbcdefdefdef
Whenever the number comes then we should repeat previous substring that many number of times.
Please provide the algorithm or code to accomplish this.

Answer 1

Here's another approach that doesn't rely on regex.
public String splitRepeat(String str)
{
StringBuilder out = new StringBuilder();
boolean number = false;
for(int i=0,j=0,k=0; i<=str.length(); i++)
{
if(i==str.length() || Character.isDigit(str.charAt(i)) != number)
{
if(number)
{
for(int r = Integer.parseInt(str.substring(j, i)); r>0; r--)
{
out.append(str.substring(k, j));
}
}
else
{
k=j;
}
j=i;
number = !number;
}
}
return out.toString();
}

Answer 2

My suggestion would be:
Try using regex so you can get an array of numbers and characters,
then convert the number Parsable elements of the array into an integer,
after that loop with the index of the arrays to append n-times the characters of the array
then print the final result
Example:
public static void main(String[] args) {
String stringToProcess = "a1bc2def3";
String[] regexSplitted = stringToProcess.split("(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)");
StringBuilder sb = new StringBuilder();
String appender = "";
for (int i = 0; i < regexSplitted.length; i++) {
try {
int kilo = Integer.parseInt(regexSplitted[i]);
for (int j = 0; j < kilo; j++) {
sb.append(appender).append(regexSplitted[i - 1]);
appender = "-";
}
} catch (NumberFormatException e) {
}
}
System.out.println(sb.toString());
}
this will print
a-bc-bc-def-def-def
that is pretty much what you are looking for.