Method to generate all permuatuons of spinnable strings
I've implemented a simple method to solve this problem.
It takes an ArrayList argument containing spinnable text string(s).
I use it to generate all the permutations of multiple spinnable strings.
It comes with extra functionality of support of optional blocks, surronded by "[ ]" brackets.
Eq.:
If you have a single string object in the ArrayList with content of:
{A | {B1 | B2 } [B optional] }
It populates the array list with all the permutations, "extracted"
Contents after invocation of method:
A
B1
B1 B optional
B2
B2 B optional
You can also pass multiple strings as argument to generate permutations for all of them:
Eg.:
Input:
ArraList with two string
{A1 | A2}
{B1 | B2}
Contents after invocation:
A1
A2
B1
B2
This implementation works by always finding the inner most bracket pair in the first spinnable section, then extract it. I do this until all the special {}, [] characters are removed.
private void ExtractVersions(ArrayList list)
{
ArrayList IndicesToRemove = new ArrayList();
for (int i = 0; i < list.Count; i++)
{
string s = list[i].ToString();
int firstIndexOfCurlyClosing = s.IndexOf('}');
int firstIndexOfBracketClosing = s.IndexOf(']');
if ((firstIndexOfCurlyClosing > -1) || (firstIndexOfBracketClosing > -1))
{
char type = ' ';
int endi = -1;
int starti = -1;
if ((firstIndexOfBracketClosing == -1) && (firstIndexOfCurlyClosing > -1))
{ // Only Curly
endi = firstIndexOfCurlyClosing;
type = '{';
}
else
{
if ((firstIndexOfBracketClosing > -1) && (firstIndexOfCurlyClosing == -1))
{ // Only bracket
endi = firstIndexOfBracketClosing;
type = '[';
}
else
{
// Both
endi = Math.Min(firstIndexOfBracketClosing, firstIndexOfCurlyClosing);
type = s[endi];
if (type == ']')
{
type = '[';
}
else
{
type = '{';
}
}
}
starti = s.Substring(0, endi).LastIndexOf(type);
if (starti == -1)
{
throw new Exception("Brackets are not valid.");
}
// start index, end index and type found. -> make changes
if (type == '[')
{
// Add two new lines, one with the optional part, one without it
list.Add(s.Remove(starti, endi - starti+1));
list.Add(s.Remove(starti, 1).Remove(endi-1, 1));
IndicesToRemove.Add(i);
}
else
if (type == '{')
{
// Add as many new lines as many alternatives there are. This must be an in most bracket.
string alternatives = s.Substring(starti + 1, endi - starti - 1);
foreach(string alt in alternatives.Split('|'))
{
list.Add(s.Remove(starti,endi-starti+1).Insert(starti,alt));
}
IndicesToRemove.Add(i);
}
} // End of if( >-1 && >-1)
} // End of for loop
for (int i = IndicesToRemove.Count-1; i >= 0; i--)
{
list.RemoveAt((int)IndicesToRemove[i]);
}
}
I hope I've helped.
Maybe it is not the simplest and best implementation, but it works well for me. Please feedback, and vote!
