C#

string[] lines = File.ReadAllLines(filePath);
var barcodes = lines.Select(line => {
    string[] parts = line.Split(',');
    return parts[2];
});
var x = barcodes.GroupBy(b => b);
foreach (var y in x)
    {
    Console.WriteLine($"{y.Key} : {y.Count()}");
    }

1578456329781 : 1
1578453697235 : 3
1548795358155 : 1

Quote:

I was thinking on using one loop to go threw the list, and then use the second loop to check for duplicates and count.

private readonly string bcdata = @"2020-07-08,13:54:16,1578456329781
2020-07-08,14:07:13,1578453697235
2020-07-08,14:08:03,1548795358155
2020-07-08,14:11:09,1578453697235
2020-07-08,14:11:42,1578453697235";

private char[] splitwhtspc = {'\r', '\n', ' ', '\t'};
private char[] splitcomma = {','};

// in some method or event-handler body:

var lines = bcdata.Split(splitwhtspc, StringSplitOptions.RemoveEmptyEntries);

Dictionary<DateTime, Int64> dttobc = lines.Select
(
    line => line.Split(splitcomma, StringSplitOptions.RemoveEmptyEntries)
).Select
(
    sary =>
        new
        {
            key = DateTime.Parse(sary[0] + " " + sary[1]),
            value = long.Parse(sary[2])
        }
)
.ToDictionary(
    kl => kl.key,
    vl => vl.value
);

Dictionary<long, int> dups = dttobc.Values.GroupBy(v => v).ToDictionary(g => g.Key, g => g.Count());

private void button4_Click(object sender, EventArgs e)
       {
           //if (!(mhdDevice.IsOpen))
           //{
           var devives = HidDevices.Enumerate(0x9915, 0x1116);
           _device = devives.First();
           _device.OpenDevice();

           _device.Inserted += DeviceAttachedHandler;
           _device.Removed += DeviceRemovedHandler;
           _device.MonitorDeviceEvents = true;

           _device.Write(new byte[] { 0, 81, 80 });

           _device.ReadReport(OnReport);
           _device.CloseDevice();

       }

private void DeviceAttachedHandler()
        {
            _device.ReadReport(OnReport);
        }
        private static void DeviceRemovedHandler()
        {
            Console.WriteLine("Device Removed");
        }
        private void OnReport(HidReport report)
        {
            if (!_device.IsConnected) { return; }

            var cardData = report.Data;
            str = Encoding.ASCII.GetString(cardData);
            if (str == null)
            {
                _device.ReadReport(OnReport);
            }
            else
            {
                MessageBox.Show("String");
            }
        }

private Random rand = new Random();
private decimal GetRandom(decimal min, decimal max)
    {
    return ((decimal)rand.Next((int)(min * 100.0M), (int)(max * 100.0M))) / 100.0M;
    }

private Random rand = new Random();

// returns a random decimal value in the range [min, max)
// allowing for steps different outcomes.
public decimal GetRandom(decimal min, decimal max, int steps=10000) {
    if (steps<=0) throw new ApplicationException("steps must be >= 1");
    int r = rand.Next(0, steps);
    return ((steps-r)*min+r*max)/steps;
}

Sajo Nezic wrote:

I need help with generating random decimal numbers from 5 to 6 (For example 5.1, 5.2 etc.)

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Sajo Nezic wrote:

It often throws out various errors to me

BillWoodruff wrote:

There is a lengthy discussion (with code examples) of generating random decimal numbers in C# here: [^].