I have the following code:
Dictionary<DayOfWeek, List<TimeSpan>> Daily = new Dictionary<DayOfWeek, List<TimeSpan>>();
The idea is that i can add a day with a time to the Daily dictionary. But a job can execute on the same day more than once.
so Daily can look like this:
{ "Monday" : [{"Hour":10, "Minute": 15}, {"Hour": 8, "Minute":5}] }
Now i would like to get the next execution datetime.
private void UpdateNextExecutionTime()
{
TimeSpan t = new TimeSpan(15, 15, 0);
DayOfWeek current = DateTime.Now.DayOfWeek;
DayOfWeek tmp = current;
TimeSpan time = new TimeSpan(DateTime.Now.Hour, DateTime.Now.Minute, DateTime.Now.Second);
int cur = (int)current;
for(int i = 0; i < 7; i++) {
if(Daily.ContainsKey((DayOfWeek)cur)) {
tmp = (DayOfWeek)cur;
/* stuck */
continue;
}
cur++;
if (cur >= 7)
cur = 0;
}
}
I managed to get the first upcoming day (including today) in the Daily dictionary but i'm stuck on the getting the time.
How would i be able to do this?
Assuming t is the time you're using as the point at which you'd like to find the next execution time, put this where you have 'stuck' (edit; just realized you changed to using TimeSpan in your list):
var execTimes = Daily[tmp];
if (execTimes != null) {
var nextTime = execTimes.OrderBy(x => x).FirstOrDefault(x => x > t);
if (nextTime != default(TimeSpan)) {
// do something...
}
}
You can also have the day in the TimeSpan,
Here is a simple example the finds the next date:
var schedule = new List<TimeSpan>{
new TimeSpan(0,16,30,0),
new TimeSpan(1,16,30,0),
new TimeSpan(5,16,30,0)
};
var monday = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek + 1);
var fromMonday = DateTime.Now - monday;
var next = schedule.OrderBy(t => t).FirstOrDefault(t => t > fromMonday);
Console.Write(monday + next - DateTime.Now);
I've got a thread that is only set to run within a certain period otherwise it's put on delay. From the time of running that threads of a certain Boolean value if true, then it should be delayed by X amount of time from current time to 18:00. Is there a quick way doing this in c#?
DateTime today = DateTime.Now;
DateTime tomorrow = today.Add(new TimeSpan(1,0,0,0));
DateTime tomorrowAtSix = new DateTime(tomorrow.Year, tomorrow.Month, tomorrow.Day, 18,0,0 );
TimeSpan diff = tomorrowAtSix.Subtract(DateTime.Now);
double hoursFromNow = 0d;
double minutesFromNow = 0d;
if(diff.TotalHours > 24d) // next 6pm is tomorrow
{
hoursFromNow = diff.TotalHours - 24d;
minutesFromNow = diff.TotalMinutes - (24d * 60d);
}
else // next 6pm is today
{
hoursFromNow = diff.TotalHours;
minutesFromNow = diff.TotalMinutes;
}
You can subtract DateTime objects which will return a TimeSpan
TimeSpan ts = DateTime.Now - new DateTime(2017, 1, 1);
How to make newTime as a global variable?
It should be added 30 minutes in time and use it in a condition. It is necessary to make var newTime as global var.
if (timerCheck == 0)
{
var today = DateTime.Now;
var interval = new TimeSpan(00, 30, 00);
var newTime = today + interval;
timerCheck = 1;
}
if (timerCheck == 1)
{
var today = DateTime.Now;
if (today >= newTime)
{
You can do it like this
public static class GlobalVariables
{
public static DateTime NewTime { get; set; }
}
Then call it like this:
if (today >= GlobalVariables.NewTime)
Just move it outside if.
I don't test it, but It might work.
DateTime newTime;
if (timerCheck == 0)
{
var today = DateTime.Now;
var interval = new TimeSpan(00, 30, 00);
newTime = today + interval;
timerCheck = 1;
}
if (timerCheck == 1)
{
if (newTime.Equals(default(DateTime)) return; // don't sure is it required or not
var today = DateTime.Now;
if (today >= newTime)
{
Well i think you should put it outside the body of If first as a variable then use it in the condition.
I want to get the first day and last day of the month where a given date lies in. The date comes from a value in a UI field.
If I'm using a time picker I could say
var maxDay = dtpAttendance.MaxDate.Day;
But I'm trying to get it from a DateTime object. So if I have this...
DateTime dt = DateTime.today;
How to get first day and last day of the month from dt?
DateTime structure stores only one value, not range of values. MinValue and MaxValue are static fields, which hold range of possible values for instances of DateTime structure. These fields are static and do not relate to particular instance of DateTime. They relate to DateTime type itself.
Suggested reading: static (C# Reference)
UPDATE: Getting month range:
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddDays(-1);
UPDATE: From comments (#KarlGjertsen & #SergeyBerezovskiy)
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddSeconds(-1);
//OR
var lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddTicks(-1);
This is more a long comment on #Sergey and #Steffen's answers. Having written similar code myself in the past I decided to check what was most performant while remembering that clarity is important too.
Result
Here is an example test run result for 10 million iterations:
2257 ms for FirstDayOfMonth_AddMethod()
2406 ms for FirstDayOfMonth_NewMethod()
6342 ms for LastDayOfMonth_AddMethod()
4037 ms for LastDayOfMonth_AddMethodWithDaysInMonth()
4160 ms for LastDayOfMonth_NewMethod()
4212 ms for LastDayOfMonth_NewMethodWithReuseOfExtMethod()
2491 ms for LastDayOfMonth_SpecialCase()
Code
I used LINQPad 4 (in C# Program mode) to run the tests with compiler optimization turned on. Here is the tested code factored as Extension methods for clarity and convenience:
public static class DateTimeDayOfMonthExtensions
{
public static DateTime FirstDayOfMonth_AddMethod(this DateTime value)
{
return value.Date.AddDays(1 - value.Day);
}
public static DateTime FirstDayOfMonth_NewMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static DateTime LastDayOfMonth_AddMethod(this DateTime value)
{
return value.FirstDayOfMonth_AddMethod().AddMonths(1).AddDays(-1);
}
public static DateTime LastDayOfMonth_AddMethodWithDaysInMonth(this DateTime value)
{
return value.Date.AddDays(DateTime.DaysInMonth(value.Year, value.Month) - value.Day);
}
public static DateTime LastDayOfMonth_SpecialCase(this DateTime value)
{
return value.AddDays(DateTime.DaysInMonth(value.Year, value.Month) - 1);
}
public static int DaysInMonth(this DateTime value)
{
return DateTime.DaysInMonth(value.Year, value.Month);
}
public static DateTime LastDayOfMonth_NewMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, DateTime.DaysInMonth(value.Year, value.Month));
}
public static DateTime LastDayOfMonth_NewMethodWithReuseOfExtMethod(this DateTime value)
{
return new DateTime(value.Year, value.Month, value.DaysInMonth());
}
}
void Main()
{
Random rnd = new Random();
DateTime[] sampleData = new DateTime[10000000];
for(int i = 0; i < sampleData.Length; i++) {
sampleData[i] = new DateTime(1970, 1, 1).AddDays(rnd.Next(0, 365 * 50));
}
GC.Collect();
System.Diagnostics.Stopwatch sw = System.Diagnostics.Stopwatch.StartNew();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].FirstDayOfMonth_AddMethod();
}
string.Format("{0} ms for FirstDayOfMonth_AddMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].FirstDayOfMonth_NewMethod();
}
string.Format("{0} ms for FirstDayOfMonth_NewMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_AddMethod();
}
string.Format("{0} ms for LastDayOfMonth_AddMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_AddMethodWithDaysInMonth();
}
string.Format("{0} ms for LastDayOfMonth_AddMethodWithDaysInMonth()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_NewMethod();
}
string.Format("{0} ms for LastDayOfMonth_NewMethod()", sw.ElapsedMilliseconds).Dump();
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_NewMethodWithReuseOfExtMethod();
}
string.Format("{0} ms for LastDayOfMonth_NewMethodWithReuseOfExtMethod()", sw.ElapsedMilliseconds).Dump();
for(int i = 0; i < sampleData.Length; i++) {
sampleData[i] = sampleData[i].FirstDayOfMonth_AddMethod();
}
GC.Collect();
sw.Restart();
for(int i = 0; i < sampleData.Length; i++) {
DateTime test = sampleData[i].LastDayOfMonth_SpecialCase();
}
string.Format("{0} ms for LastDayOfMonth_SpecialCase()", sw.ElapsedMilliseconds).Dump();
}
Analysis
I was surprised by some of these results.
Although there is not much in it the FirstDayOfMonth_AddMethod was slightly faster than FirstDayOfMonth_NewMethod in most runs of the test. However, I think the latter has a slightly clearer intent and so I have a preference for that.
LastDayOfMonth_AddMethod was a clear loser against LastDayOfMonth_AddMethodWithDaysInMonth, LastDayOfMonth_NewMethod and LastDayOfMonth_NewMethodWithReuseOfExtMethod. Between the fastest three there is nothing much in it and so it comes down to your personal preference. I choose the clarity of LastDayOfMonth_NewMethodWithReuseOfExtMethod with its reuse of another useful extension method. IMHO its intent is clearer and I am willing to accept the small performance cost.
LastDayOfMonth_SpecialCase assumes you are providing the first of the month in the special case where you may have already calculated that date and it uses the add method with DateTime.DaysInMonth to get the result. This is faster than the other versions, as you would expect, but unless you are in a desperate need for speed I don't see the point of having this special case in your arsenal.
Conclusion
Here is an extension method class with my choices and in general agreement with #Steffen I believe:
public static class DateTimeDayOfMonthExtensions
{
public static DateTime FirstDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static int DaysInMonth(this DateTime value)
{
return DateTime.DaysInMonth(value.Year, value.Month);
}
public static DateTime LastDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, value.DaysInMonth());
}
}
If you have got this far, thank you for time! Its been fun :¬). Please comment if you have any other suggestions for these algorithms.
Getting month range with .Net API (just another way):
DateTime date = ...
var firstDayOfMonth = new DateTime(date.Year, date.Month, 1);
var lastDayOfMonth = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
"Last day of month" is actually "First day of *next* month, minus 1". So here's what I use, no need for "DaysInMonth" method:
public static DateTime FirstDayOfMonth(this DateTime value)
{
return new DateTime(value.Year, value.Month, 1);
}
public static DateTime LastDayOfMonth(this DateTime value)
{
return value.FirstDayOfMonth()
.AddMonths(1)
.AddMinutes(-1);
}
NOTE:
The reason I use AddMinutes(-1), not AddDays(-1) here is because usually you need these date functions for reporting for some date-period, and when you build a report for a period, the "end date" should actually be something like Oct 31 2015 23:59:59 so your report works correctly - including all the data from last day of month.
I.e. you actually get the "last moment of the month" here. Not Last day.
OK, I'm going to shut up now.
DateTime dCalcDate = DateTime.Now;
dtpFromEffDate.Value = new DateTime(dCalcDate.Year, dCalcDate.Month, 1);
dptToEffDate.Value = new DateTime(dCalcDate.Year, dCalcDate.Month, DateTime.DaysInMonth(dCalcDate.Year, dCalcDate.Month));
Here you can add one month for the first day of current month than delete 1 day from that day.
DateTime now = DateTime.Now;
var startDate = new DateTime(now.Year, now.Month, 1);
var endDate = startDate.AddMonths(1).AddDays(-1);
If you only care about the date
var firstDay = new DateTime(date.Year, date.Month, 1, 0, 0, 0, date.Kind);
var lastDay = new DateTime(date.Year, date.Month, 1, 0, 0, 0, date.Kind).AddMonths(1).AddDays(-1);
If you want to preserve time
var firstDay = new DateTime(date.Year, date.Month, 1, date.Hour, date.Minute, date.Second, date.Kind);
var lastDay = new DateTime(date.Year, date.Month, 1, date.Hour, date.Minute, date.Second, date.Kind).AddMonths(1).AddDays(-1);
Try this one:
string strDate = DateTime.Now.ToString("MM/01/yyyy");
The accepted answer here does not take into account the Kind of the DateTime instance. For example if your original DateTime instance was a UTC Kind then by making a new DateTime instance you will be making an Unknown Kind instance which will then be treated as local time based on server settings. Therefore the more proper way to get the first and last date of the month would be this:
var now = DateTime.UtcNow;
var first = now.Date.AddDays(-(now.Date.Day - 1));
var last = first.AddMonths(1).AddTicks(-1);
This way the original Kind of the DateTime instance is preserved.
I used this in my script(works for me) but I needed a full date without the need of trimming it to only the date and no time.
public DateTime GetLastDayOfTheMonth()
{
int daysFromNow = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month) - (int)DateTime.Now.Day;
return DateTime.Now.AddDays(daysFromNow);
}
For Persian culture
PersianCalendar pc = new PersianCalendar();
var today = pc.GetDayOfMonth(DateTime.Now);
var firstDayOfMonth = pc.GetDayOfMonth(DateTime.Now.AddDays(-(today-1)));
var lastDayOfMonth = pc.GetDayOfMonth(DateTime.Now.AddMonths(1).AddDays(-today));
Console.WriteLine("First day "+ firstDayOfMonth);
Console.WriteLine("Last day " + lastDayOfMonth);
You can do it
DateTime dt = DateTime.Now;
DateTime firstDayOfMonth = new DateTime(dt.Year, date.Month, 1);
DateTime lastDayOfMonth = firstDayOfMonth.AddMonths(1).AddDays(-1);
Give this a try. It basically calculates the number of days that has passed on DateTime.Now, then subtracts one from that and uses the new value to find the first of the current month. From there it uses that DateTime and uses .AddMonths(-1) to get the first of the previous month.
Getting the last day of last month does basically the same thing except it adds one to number of days in the month and subtracts that value from DateTime.Now.AddDays, giving you the last day of the previous month.
int NumberofDays = DateTime.Now.Day;
int FirstDay = NumberofDays - 1;
int LastDay = NumberofDays + 1;
DateTime FirstofThisMonth = DateTime.Now.AddDays(-FirstDay);
DateTime LastDayOfLastMonth = DateTime.Now.AddDays(-LastDay);
DateTime CheckLastMonth = FirstofThisMonth.AddMonths(-1);
You can try this for get current month first day;
DateTime.Now.AddDays(-(DateTime.Now.Day-1))
and assign it a value.
Like this:
dateEndEdit.EditValue = DateTime.Now;
dateStartEdit.EditValue = DateTime.Now.AddDays(-(DateTime.Now.Day-1));
Create an instance of DateTime class
DateTime dateTime = DateTime.Now;
If you want to get the last day of the month you can do this
int lastDayOfMonth = DateTime.DaysInMonth(caducidadPuntos.Year, caducidadPuntos.Month);
If you want to get the first day of the month, you can do this
DateTime firstDayMonth = new DateTime(dateTime.Year, dateTime.Month, 1);
We had the requirement of being able to get the start and end of a given dates month, including times, inclusively. We ended up utilizing the aforementioned solutions, huge thanks to everyone here, and combined it into a util class to be able to get the start and end for a given month and year number combination up to the last millisecond. Including what we moved forward with in the event it helps someone else.
The util:
public class DateUtil
{
public static (DateTime startOfMonth, DateTime endOfMonth) GetStartAndEndOfMonth(int month, int year)
{
DateTime startOfMonth = GetStartOfMonth(month, year);
DateTime endOfMonth = GetEndOfMonth(month, year);
return (startOfMonth, endOfMonth);
}
public static DateTime GetStartOfMonth(int month, int year)
{
return new DateTime(year, month, 1).Date;
}
public static DateTime GetEndOfMonth(int month, int year)
{
return new DateTime(year, month, 1).Date.AddMonths(1).AddMilliseconds(-1);
}
}
Usage:
(DateTime startOfMonth, DateTime endOfMonth) = DateUtil.GetStartAndEndOfMonth(2, 2021); // February, 2021
easy way to do it
Begin = new DateTime(DateTime.Now.Year, DateTime.Now.Month,1).ToShortDateString();
End = new DataFim.Text = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month)).ToShortDateString();
DateTime dCalcDate = DateTime.Now;
var startDate = new DateTime(Convert.ToInt32(Year), Convert.ToInt32(Month), 1);
var endDate = new DateTime(Convert.ToInt32(Year), Convert.ToInt32(Month), DateTime.DaysInMonth((Convert.ToInt32(Year)), Convert.ToInt32(Month)));
Assuming you have a Unix timestamp, what would be an easy and/or elegant way to check if that timestamp was some time yesterday?
I am mostly looking for solutions in Javascript, PHP or C#, but pseudo code and language agnostic solutions (if any) are welcome as well.
In C# you could use this:
bool isYesterday = DateTime.Today - time.Date == TimeSpan.FromDays(1);
You can use this in C#:
bool isYesterday = (dateToCheck.Date.AddDays(1) == DateTime.Now.Date);
PHP:
$isYesterday = date('Ymd', $timestamp) == date('Ymd', strtotime('yesterday'));
In pseudo code, to compare timestamps:
get current Unix timestamp
transform the retrieved timestamp to a date
subtract 1 day from the date
transform the timestamp to test to a date
compare both dates. If they're equal the tested timestamp was yesterday.
Watch out for timezones if you show the results to a user. For me it's now 13:39 on July 9 2010. A timestamp for 14 hours ago for me is yesterday. But for someone in a different timezone where it's now 15:39, 14 hours ago wasn't yesterday!
Another problem might be systems with a wrong time/date setup. For example if you use JavaScript and the system time of the visitors PC is wrong, the program may come to a wrong conclusion. If it's essential to get a correct answer, retrieve the current time from a known source with a correct time.
An example in Smalltalk using Pharo/Squeak
(Date year: 2014 month: 4 day: 24) = Date yesterday
This accepts an optional DateTimeZone object. If it's not given, it uses the currently set default timezone.
<?php
function isYesterday($timestamp, $timezone = null) {
$t = new DateTime(null, $timezone);
$t->setTimestamp($timestamp);
$t->setTime(0,0);
$yesterday = new DateTime("now", $timezone);
$yesterday->setTime(0,0);
$yesterday = $yesterday->sub(new DateInterval('P1D'));
return $t == $yesterday;
}
Another C# example:
bool isYesterday = DateTime.Now.Date.AddDays(-1) == dateToCheck.Date;
Code:
static class ExtensionMethods
{
private static readonly DateTime UnixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0);;
public static bool IsYesterday(this int unixTime)
{
DateTime convertedTime = UnixStart.AddSeconds(unixTime);
return convertedTime.Date == DateTime.Now.AddDays(-1).Date;
}
public static bool IsYesterday(this DateTime date)
{
return date.Date == DateTime.Now.AddDays(-1).Date;
}
}
Examples:
public class Examples
{
public void Tests()
{
if (1278677571.IsYesterday()) System.Console.WriteLine("Is yesterday");
DateTime aDate = new DateTime(2010, 12, 31);
if (aDate.IsYesterday()) System.Console.WriteLine("Is yesterday");
}
}
In JavaScript, you could write
var someDate = new Date(2010, 6, 9);
Date.yesterday.date == someDate.date // true
Left out needless implementation details, but it's possible. Ok, there ya go :)
(function() {
function date(d) {
var year = d.getFullYear();
var month = d.getMonth();
var day = d.getDate();
return new Date(year, month, day);
}
Object.defineProperty(Date, 'yesterday', {
enumerable: true,
configurable: false,
get: function() {
var today = new Date();
var millisecondsInADay = 86400000;
var yesterday = new Date(today - millisecondsInADay);
return yesterday;
},
set: undefined
});
Object.defineProperty(Date.prototype, 'date', {
enumerable: true,
configurable: true,
get: function() {
return date(this).valueOf();
},
set: undefined
});
})();
C#
TimeSpan difference = DateTime.Now.Date - olderDate.Date;
bool isYesterday = difference.TotalDays == 1;
You can give this function a shot:
public bool IsFromYesterday(long unixTime) {
DateTime convertedTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);
convertedTime.AddSeconds(unixTime);
DateTime rightNow = DateTime.Now;
DateTime startOfToday = DateTime.Today;
DateTime startOfYesterday = startOfToday - new TimeSpan(1, 0, 0, 0);
if (convertedTime > startOfYesterday && convertedTime < rightNow)
return true;
else
return false;
}