For example: Let's say I wanted a random time from the date 01/03/20 -> It can return 23:23:45 or 07:12:34 etc.. It that possible in C# ?
You can try:
public static DateTime GetRandomTime(DateTime date)
{
Random rnd = new Random();
return date.Date.AddSeconds(rnd.Next(60 * 60 * 24));
}
I'm needing to generate 5 random times between 08:20:00 and 08:29:59.
These times need to be added into the top text boxes from left to right.
I'm currently doing it with this code:
private void Button1_Click(object sender, EventArgs e)
{
listBox1.Items.Clear();
Random random = new Random();
TimeSpan start = TimeSpan.FromHours(08.20);
TimeSpan end = TimeSpan.FromHours(08.30);
int maxMinutes = (int)((end - start).TotalMinutes);
for (int i = 0; i < 5; ++i)
{
int minutes = random.Next(maxMinutes);
TimeSpan t = start.Add(TimeSpan.FromMinutes(minutes));
listBox1.Items.Add(t);
}
}
And this is what it looks like.
Currently, it's not generating them between the time frame and it's also not including seconds which is critical. I also need a solution to add them into their slots.
1st generated needs to go into monday_In, 2nd needs to go into tuesday_In, 3rd needs to go to wednesday_In, 4th needs to go to thursday_In, 5th needs to go to friday_In
Any ideas on how to do this?
Firstly, 8.20 hours is not 8 hours and 20 minutes. It is 8 hours and 12 minutes. Similarly 8.30 hours is 8 hours and 18 minutes.
So you should change the way you initialise the start and end times:
var start = new TimeSpan(8, 20, 0);
var end = new TimeSpan(8, 30, 0);
Secondly, if you want to get seconds precision in generating a random time, you need the difference in seconds, not minutes:
var secondsDifference = (int)(end.TotalSeconds - start.TotalSeconds);
To get a random time, you can simply do startTime + x seconds where x is a random number between 0 and secondsDifference:
for (int i = 0 ; i < 5 ; i++) {
var randomTime = start + TimeSpan.FromSeconds(random.Next(secondsDifference));
listBox1.Items.Add(randomTime);
}
private void Button1_Click(object sender, EventArgs e)
{
listBox1.Items.Clear();
Random random = new Random();
long start = TimeSpan.FromHours(08.20).Ticks;
long end = TimeSpan.FromHours(08.30).Ticks;
for (int i = 0; i < 5; ++i)
{
long ticks = random.NextLong(start, end);
TimeSpan t = TimeSpan.FromTicks(ticks);
listBox1.Items.Add(t);
}
}
edit
forgot that it was a custom extension
public static long NextLong(this Random random, long minValue, long maxValue)
{
long dif = maxValue - minValue;
return (long)Math.Round((random.NextDouble() * dif) + minValue);
}
I have datetime like 2019-02-10 20:39:23 and I want to round this time to the next one apart 15 min to the closest one. So it means the next one should be 2019-02-10 21:45:00 or another example 21:24:17 should became 21:45:00... The code below works fine until I have datetime like 2019-02-10 23:54:20. Then the next one rounded should be 2019-03-10 00:00:00 but I get 2019-02-10 00:00:00.
Here is how I'm doing it:
static void Main(string[] args)
{
DateTime dt = DateTime.Parse("2019-02-10 23:54:23");
var interval = TimeSpan.FromMinutes(15);
DateTime last = NextTime(dt, interval);
Console.WriteLine(last);
}
private static DateTime NextTime(DateTime value, TimeSpan interval)
{
var temp = value.Add(new TimeSpan(interval.Ticks / 2));
var time = new TimeSpan((temp.TimeOfDay.Ticks / interval.Ticks) * interval.Ticks);
return value.Date.Add(time);
}
For output I get 2019-02-10 00:00:00 instead of 2019-03-10 00:00:00
Can't figure out why doesn't turn to next day...
The return value is being calculated from the wrong variable. Use temp instead of value:
private static DateTime NextTime(DateTime value, TimeSpan interval)
{
var temp = value.Add(new TimeSpan(interval.Ticks / 2));
var time = new TimeSpan((temp.TimeOfDay.Ticks / interval.Ticks) * interval.Ticks);
return temp.Date.Add(time);
}
The reason for this is because you're adding your interval to the value. If it rolls over a midnight/end of day your value.Date will return the wrong day. Since you store temp, you can return temp.Date.Add(time)
Using DateTime.Add(TimeSpan) the time is concat in the date.
I'v changed your code in this way and it did the trick:
private static DateTime NextTime(DateTime value, TimeSpan interval)
{
var temp = value.Add(new TimeSpan(interval.Ticks / 2));
var time = new TimeSpan((temp.TimeOfDay.Ticks / interval.Ticks) * interval.Ticks);
if (time == new TimeSpan(0, 0, 0)) { time = new TimeSpan(24, 0,0); }
var timeDiff = time - value.TimeOfDay;
var finalDate = value.AddHours(timeDiff.Hours);
finalDate = finalDate.AddMinutes(timeDiff.Minutes);
finalDate = finalDate.AddSeconds(timeDiff.Seconds);
return finalDate;
}
I believe that must have some way more beautifull to do that but it works.
My objective is to populate a combo box with time intervals of 30 min for 24 hours. I.E - 12.00am, 12.30am, 1.00am, 1.30am and so on. I need to know how to put these details into array. Thank you
Perhaps:
string[] comboboxDataSource = Enumerable.Range(0, 2 * 24)
.Select(min => DateTime.Today.AddMinutes(30 * min).ToString("h.mmtt", CultureInfo.InvariantCulture))
.ToArray();
One way is to iterate 30 minutes in a day and add this DateTime values with a specific string representation to your list. Like;
List<string> list = new List<string>();
DateTime start = DateTime.Today;
DateTime end = DateTime.Today.AddDays(1);
while (end > start)
{
list.Add(start.ToString("h.mmtt", CultureInfo.InvariantCulture));
start = start.AddMinutes(30);
}
If you wanna get them as an array, just use list.ToArray() to get it. Also time designators are in .NET Framework are mostly (I haven't check all of them) upper case. That means, you will get AM or PM when you use tt specifier, not am or pm. In such a case, you need to replace these values with their lower cases.
Don't know exactly what you mean. I would start with something like this:
private IEnumerable<Timespan> Get30MinuteIntervalls()
{
var currentValue = new Timespan(0);
while (currentValue <= Timespan.FromHours(24)
{
yield return currentValue;
currentValue = currentValue.Add(Timespan.FromMinutes(30));
}
}
var values = Get30MinuteIntervalls().ToArray();
Try:
var d = new DateTime();
d = d.Date.AddHours("0").AddMinutes("0");
for (int i = 0; i < 48; i++)
{
d.AddMinutes(30);
cbo.AddItem(d.TimeOfDay.ToString());
}
I'm looking for some succinct, modern C# code to generate a random date between Jan 1 1995 and the current date.
I'm thinking some solution that utilizes Enumerable.Range somehow may make this more succinct.
private Random gen = new Random();
DateTime RandomDay()
{
DateTime start = new DateTime(1995, 1, 1);
int range = (DateTime.Today - start).Days;
return start.AddDays(gen.Next(range));
}
For better performance if this will be called repeatedly, create the start and gen (and maybe even range) variables outside of the function.
This is in slight response to Joel's comment about making a slighly more optimized version. Instead of returning a random date directly, why not return a generator function which can be called repeatedly to create a random date.
Func<DateTime> RandomDayFunc()
{
DateTime start = new DateTime(1995, 1, 1);
Random gen = new Random();
int range = ((TimeSpan)(DateTime.Today - start)).Days;
return () => start.AddDays(gen.Next(range));
}
I have taken #Joel Coehoorn answer and made the changes he adviced - put the variable out of the method and put all in class. Plus now the time is random too. Here is the result.
class RandomDateTime
{
DateTime start;
Random gen;
int range;
public RandomDateTime()
{
start = new DateTime(1995, 1, 1);
gen = new Random();
range = (DateTime.Today - start).Days;
}
public DateTime Next()
{
return start.AddDays(gen.Next(range)).AddHours(gen.Next(0,24)).AddMinutes(gen.Next(0,60)).AddSeconds(gen.Next(0,60));
}
}
And example how to use to write 100 random DateTimes to console:
RandomDateTime date = new RandomDateTime();
for (int i = 0; i < 100; i++)
{
Console.WriteLine(date.Next());
}
Well, if you gonna present alternate optimization, we can also go for an iterator:
static IEnumerable<DateTime> RandomDay()
{
DateTime start = new DateTime(1995, 1, 1);
Random gen = new Random();
int range = ((TimeSpan)(DateTime.Today - start)).Days;
while (true)
yield return start.AddDays(gen.Next(range));
}
you could use it like this:
int i=0;
foreach(DateTime dt in RandomDay())
{
Console.WriteLine(dt);
if (++i == 10)
break;
}
Start with a fixed date object (Jan 1, 1995), and add a random number of days with AddDays (obviusly, pay attention not surpassing the current date).
Random rnd = new Random();
DateTime datetoday = DateTime.Now;
int rndYear = rnd.Next(1995, datetoday.Year);
int rndMonth = rnd.Next(1, 12);
int rndDay = rnd.Next(1, 31);
DateTime generateDate = new DateTime(rndYear, rndMonth, rndDay);
Console.WriteLine(generateDate);
//this maybe is not the best method but is fast and easy to understand
One more solution to the problem, this time a class to which you provide a range you want the dates in. Its down to random minutes in the results.
/// <summary>
/// A random date/time class that provides random dates within a given range
/// </summary>
public class RandomDateTime
{
private readonly Random rng = new Random();
private readonly int totalMinutes;
private readonly DateTime startDateTime;
/// <summary>
/// Initializes a new instance of the <see cref="RandomDateTime"/> class.
/// </summary>
/// <param name="startDate">The start date.</param>
/// <param name="endDate">The end date.</param>
public RandomDateTime(DateTime startDate, DateTime endDate)
{
this.startDateTime = startDate;
TimeSpan timeSpan = endDate - startDate;
this.totalMinutes = (int)timeSpan.TotalMinutes;
}
/// <summary>
/// Gets the next random datetime object within the range of startDate and endDate provided in the ctor
/// </summary>
/// <returns>A DateTime.</returns>
public DateTime NextDateTime
{
get
{
TimeSpan newSpan = new TimeSpan(0, rng.Next(0, this.totalMinutes), 0);
return this.startDateTime + newSpan;
}
}
}
Use it like this to spit out 5 random dates between january 1st 2020 and december 31 2022:
RandomDateTime rdt = new RandomDateTime(DateTime.Parse("01/01/2020"), DateTime.Parse("31/12/2022"));
for (int i = 0; i < 5; i++)
Debug.WriteLine(rdt.NextDateTime);
I am a bit late in to the game, but here is one solution which works fine:
void Main()
{
var dateResult = GetRandomDates(new DateTime(1995, 1, 1), DateTime.UtcNow, 100);
foreach (var r in dateResult)
Console.WriteLine(r);
}
public static IList<DateTime> GetRandomDates(DateTime startDate, DateTime maxDate, int range)
{
var randomResult = GetRandomNumbers(range).ToArray();
var calculationValue = maxDate.Subtract(startDate).TotalMinutes / int.MaxValue;
var dateResults = randomResult.Select(s => startDate.AddMinutes(s * calculationValue)).ToList();
return dateResults;
}
public static IEnumerable<int> GetRandomNumbers(int size)
{
var data = new byte[4];
using (var rng = new System.Security.Cryptography.RNGCryptoServiceProvider(data))
{
for (int i = 0; i < size; i++)
{
rng.GetBytes(data);
var value = BitConverter.ToInt32(data, 0);
yield return value < 0 ? value * -1 : value;
}
}
}
Small method that returns a random date as string, based on some simple input parameters. Built based on variations from the above answers:
public string RandomDate(int startYear = 1960, string outputDateFormat = "yyyy-MM-dd")
{
DateTime start = new DateTime(startYear, 1, 1);
Random gen = new Random(Guid.NewGuid().GetHashCode());
int range = (DateTime.Today - start).Days;
return start.AddDays(gen.Next(range)).ToString(outputDateFormat);
}
Useful extension based of #Jeremy Thompson's solution
public static class RandomExtensions
{
public static DateTime Next(this Random random, DateTime start, DateTime? end = null)
{
end ??= new DateTime();
int range = (end.Value - start).Days;
return start.AddDays(random.Next(range));
}
}