Increase number until mets condition-CodePudding

I have creation of tenant

Here is code

 var tenant = new Tenant(tenancyName, name)
            {
                IsActive = isActive,
                EditionId = editionId,
                SubscriptionEndDateUtc = subscriptionEndDate?.ToUniversalTime(),
                IsInTrialPeriod = isInTrialPeriod,
                ConnectionString = connectionString.IsNullOrWhiteSpace()
                    ? null
                    : SimpleStringCipher.Instance.Encrypt(connectionString)
            };
           
            
            await CreateAsync(tenant);
            await _unitOfWorkManager.Current.SaveChangesAsync(); //To get new tenant's id.

tenancyName can be duplicated

So for checking it I use this condition

            if (await TenantRepository.FirstOrDefaultAsync(t => t.TenancyName == tenant.TenancyName) != null)
            {
                
            }

I need to add a count to it to be unique.

So for example, if EugeneTenant is duplicated, I need to add 2 to it, to be EugeneTenant2,

if EugeneTenant2 is duplicated, add 3 to it, so EugeneTenant3

So it will be autoincremented from 2 until the condition will meet.

I added this code

   int startNumber = 2;
            do
            {
                tenant.TenancyName = $"{tenant.TenancyName}{startNumber}";
                tenant.Name = $"{tenant.TenancyName}{startNumber}";
                startNumber  ;
            }
            while (await TenantRepository.FirstOrDefaultAsync(t => t.TenancyName == tenant.TenancyName) != null);

But for Example if I have EugeneTenancy2, next one I have, EugeneTenancy23

How I can do this?

CodePudding user response：

var name = "EugeneTenant";
var names = TenantRepository
    .Where(t => t.TenancyName == tenant.TenancyName)
    .OrderByDescending(t => t.TenancyName)
    .Select(x => x.TenancyName);

if (names.Any()) 
{
    var cnt = Regex.Match(names.First(), @"\d*")?.Value;
    var _ = int.TryParse($"{cnt}", out int n);

    name  = n > 2 ? n   1 : 2;
}

CodePudding user response：

If you would use a delimiter between the name and the counter (like EugeneTenancy-2) then you can get rid of startNumber counter.

const string Delimiter = "-"; 
var tenancyName = tenant.TenancyName;

string[] parts = tenancyName.Split(Delimiter);
if(parts.Length == 1)
{
   tenancyName = $"{tenancyName}{Delimiter}2";
}
else
{
   int counter = int.Parse(parts[1]);
   tenancyName = $"{tenancyName}{Delimiter}{  counter}";
}

tenant.TenancyName = tenancyName;
tenant.Name = tenancyName;

Obviously this code is super fragile (.Length == 1,parts[1], int.Parse, etc.) but you get the idea how to rely on a data, which is already available inside the TenancyName.

In other words this is not a robust code, it is created for demonstration purposes only.

UPDATE #1: If no delimiter is allowed

Then you need to use SubString instead

char[] prefix = originalTenancyName.ToCharArray(); //store outside of the loop

string counterRaw = tenancyName.TrimStart(prefix);
int counter = int.Parse(counterRaw);