convert date with time into hour AM/PM format - reactjs

Want to covert Thu Apr 28 2022 07:00:00 GMT+0530 into 7pm
UI is like this,
also want to covert that 7pm to Thu Apr 28 2022 07:00:00 format

Try this, if it is working for you
var time = new Date('Thu Apr 28 2022 19:00:00 GMT+0530');
console.log(
time.toLocaleString('en-US', { hour: 'numeric', hour12: true })
);

You can format your date like this:
<TimePicker
showMinute={false}
showSecond={false}
use12Hours
onChange={(val, data) => {
// Thu Apr 28 2022 07:00:00 format
console.log(val?.format('ddd, MMMM D YYYY, h:mm:ss'));
}}
/>
You can read more about formatting in moment documentation. Moment Format

Related

how to take only times from dates inside array in rails

so... i need to take times from dates inside Array
so for example I have an array like this
a = [
Thu, 17 Mar 2022 10:00:00.000000000 KST +09:00,
Thu, 17 Mar 2022 10:00:00.000000000 KST +09:00,
Thu, 17 Mar 2022 14:00:00.000000000 KST +09:00,
Thu, 17 Mar 2022 14:00:00.000000000 KST +09:00,
Thu, 17 Mar 2022 17:00:00.000000000 KST +09:00]
and wanted to have result of
a = ["10:00", "10:00", "14:00", "14:00", "17:00"]
So i was trying this
can_choose =[];
a.each_with_index do |time| strftime("%H:%M")
can_choose <<|time|
but doesn't works at all...
where should I have to fix??
You can also extract the year, month, day the same way
https://ruby-doc.org/stdlib-3.1.1/libdoc/date/rdoc/Date.html
a = [
'Thu, 17 Mar 2022 10:00:00.000000000 KST +09:00',
'Thu, 17 Mar 2022 10:00:00.000000000 KST +09:00',
'Thu, 17 Mar 2022 14:00:00.000000000 KST +09:00',
'Thu, 17 Mar 2022 14:00:00.000000000 KST +09:00',
'Thu, 17 Mar 2022 17:00:00.000000000 KST +09:00']
can_choose =[]
a.map do |time|
t = DateTime.parse(time)
can_choose << t.strftime("%k:%M")
end
p can_choose
=> ["10:00", "10:00", "14:00", "14:00", "17:00"]
Ruby is all about message passing. The syntax to send a message is:
receiver.message(argument)
strftime is such message, but it needs a proper receiver. So if you have some Time instance, e.g.:
time = Time.parse('2022-03-17 10:00:00 +0900')
you'd write:
time.strftime('%H:%M') #=> "10:00"
with time being the receiver, strftime being the message and '%H:%M' being the argument.
You can use the above code in an each loop like this:
can_choose = []
a.each do |time|
can_choose << time.strftime('%H:%M')
end
Or you could use map to convert your array to another array:
can_choose = a.map { |time| time.strftime('%H:%M') }
The curly braces here { ... } are equivalent to the do ... end block above.
I would simple go with:
can_choose = a.map { |datetime| datetime.strftime('%H:%M') }
If you need only hours and minutes in 24h format, just use %R directive with Time#strftime or DateTime#strftime
can_choose = a.map { |time| time.strftime('%R') }

mktime or tz database unexpected return for 1941

mktime returns for july 3rd 1941 (00:00:00) and july 4th 1941 (00:00:00) are unexpected.
The difference between the two is 82800 seconds, lacking a full hour (3600).
The C program diff1941.c (see below) shows the following :
$> diff1941
july3=-899337600i
diff:82800 should be 86400
At first I thought it was a TZ Database hour shift, but as far as I understand, and according to zdump command, there is no such shift for 1941.
zdump -v -c 1940,1943 /etc/localtime
/etc/localtime Sun Feb 25 01:59:59 1940 UT = Sun Feb 25 01:59:59 1940 WET isdst=0 gmtoff=0
/etc/localtime Sun Feb 25 02:00:00 1940 UT = Sun Feb 25 03:00:00 1940 WEST isdst=1 gmtoff=3600
/etc/localtime Fri Jun 14 21:59:59 1940 UT = Fri Jun 14 22:59:59 1940 WEST isdst=1 gmtoff=3600
/etc/localtime Fri Jun 14 22:00:00 1940 UT = Sat Jun 15 00:00:00 1940 CEST isdst=1 gmtoff=7200
/etc/localtime Mon Nov 2 00:59:59 1942 UT = Mon Nov 2 02:59:59 1942 CEST isdst=1 gmtoff=7200
/etc/localtime Mon Nov 2 01:00:00 1942 UT = Mon Nov 2 02:00:00 1942 CET isdst=0 gmtoff=3600
So at this point I am confused. Either my program has a bug that I can not see (possible), or there is a bug in lib C mktime function(unlikely), or there is something subtle in the TZ database and I can not find it (probable): what do you think of it ?
I am using:
Ubuntu 20.04 64 bits,
libc 2.31-0ubuntu9,
tzdata 2019c-3ubuntu1
/etc/localtime points on /usr/share/zoneinfo/Europe/Paris
diff1941.c:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
long int stamp(int d,int m,int y)
{
struct tm date;
memset(&date,0,sizeof(date));
date.tm_mday=d;
date.tm_mon=m-1;
date.tm_year=y-1900;
return mktime(&date);
}
int main(int argc, char **argv)
{
if (argc>1)
setenv("TZ","0",1);
long int july3=stamp(3,7,1941);
long int july4=stamp(4,7,1941);
printf("july3=%ldi\n",july3);
printf("diff:%ld should be 86400\n",july4-july3);
}
Usually, when you see 1 hour difference in time, that means you should take a look at daylight saving time settings.
On both dates 3rd July 1941 and 4th July 1941 daylight saving time was in effect in France. You specify tm_isdst = 0, that means the daylight saving time is not in effect for your dates. So your dates are invalid - there was no such time as 3rd July 1941 with 00:00:00 with no DST.
Glibc mktime tries it's best to determine what time do you have in mind. Actually it determines the first of the dates as 3rd July 1941 02:00:00 and the second of the dates as 4th July 1941 01:00:00. The difference is one day minus one hour.
Either set isdst=-1 to let mktime "automagically" determine the current DST for your input times. In France it was DST all the time in 1941, it will determine isdst=1. Or explicit specify that you want DST by setting date.isdst=1.

Using Linux mktime to get timezone

I use the following codes to caculate timezone. When I set the timezone to Asia/Singapore, I think I should get 28800 which 28800/3600=8, it should be GMT +8, but it returns 27000/3600=7.5, Am I wrong?
struct tm tSysTime;
long int secs;
memset(&tSysTime,0,sizeof(tSysTime));
tSysTime.tm_year = 70;
tSysTime.tm_mon = 0;
tSysTime.tm_mday = 1;
tSysTime.tm_hour = 0;
tSysTime.tm_min = 0;
tSysTime.tm_sec = 0;
secs = 0-mktime(&tSysTime);
printf("[main] time zone %ld\n",secs);
Diagnosis
According to zdump -v Asia/Singapore on a Mac, the time zone offset from UTC for Singapore between August 1965 and January 1982 was 7h 30m east of UTC:
$ zdump -v Asia/Singapore
Asia/Singapore Fri Dec 13 20:45:52 1901 UTC = Sat Dec 14 03:41:17 1901 SMT isdst=0
Asia/Singapore Sat Dec 14 20:45:52 1901 UTC = Sun Dec 15 03:41:17 1901 SMT isdst=0
Asia/Singapore Wed May 31 17:04:34 1905 UTC = Wed May 31 23:59:59 1905 SMT isdst=0
Asia/Singapore Wed May 31 17:04:35 1905 UTC = Thu Jun 1 00:04:35 1905 MALT isdst=0
Asia/Singapore Sat Dec 31 16:59:59 1932 UTC = Sat Dec 31 23:59:59 1932 MALT isdst=0
Asia/Singapore Sat Dec 31 17:00:00 1932 UTC = Sun Jan 1 00:20:00 1933 MALST isdst=1
Asia/Singapore Tue Dec 31 16:39:59 1935 UTC = Tue Dec 31 23:59:59 1935 MALST isdst=1
Asia/Singapore Tue Dec 31 16:40:00 1935 UTC = Wed Jan 1 00:00:00 1936 MALT isdst=0
Asia/Singapore Sun Aug 31 16:39:59 1941 UTC = Sun Aug 31 23:59:59 1941 MALT isdst=0
Asia/Singapore Sun Aug 31 16:40:00 1941 UTC = Mon Sep 1 00:10:00 1941 MALT isdst=0
Asia/Singapore Sun Feb 15 16:29:59 1942 UTC = Sun Feb 15 23:59:59 1942 MALT isdst=0
Asia/Singapore Sun Feb 15 16:30:00 1942 UTC = Mon Feb 16 01:30:00 1942 JST isdst=0
Asia/Singapore Tue Sep 11 14:59:59 1945 UTC = Tue Sep 11 23:59:59 1945 JST isdst=0
Asia/Singapore Tue Sep 11 15:00:00 1945 UTC = Tue Sep 11 22:30:00 1945 MALT isdst=0
Asia/Singapore Sun Aug 8 16:29:59 1965 UTC = Sun Aug 8 23:59:59 1965 MALT isdst=0
Asia/Singapore Sun Aug 8 16:30:00 1965 UTC = Mon Aug 9 00:00:00 1965 SGT isdst=0
Asia/Singapore Thu Dec 31 16:29:59 1981 UTC = Thu Dec 31 23:59:59 1981 SGT isdst=0
Asia/Singapore Thu Dec 31 16:30:00 1981 UTC = Fri Jan 1 00:30:00 1982 SGT isdst=0
Asia/Singapore Mon Jan 18 03:14:07 2038 UTC = Mon Jan 18 11:14:07 2038 SGT isdst=0
Asia/Singapore Tue Jan 19 03:14:07 2038 UTC = Tue Jan 19 11:14:07 2038 SGT isdst=0
$
Consequently, the result you're getting is the correct offset from UTC in Singapore for 1970-01-01.
Subsidiary question
The current timezone of Singapore is GMT8. What I should do to fix this problem?
The current time zone offset of Singapore is UTC+8 (GMT+8), but historically (specifically, in 1970), that was not the case. You will have to devise a time nearer to the current time when the time zone offset in the database is correct. That seems to mean a time since 1982-01-01 00:30:00 +08:00. So, maybe you should use 2000-01-01 00:00:00? You'll need the number of seconds in the 30 years since 1970-01-01 00:00:00 to get the answer right, and you'll use that in place of the 0 in 0 - mktime(&tSysTime). I believe the relevant number is 946684800.
Revised C code
#include <stdio.h>
#include <string.h>
#include <time.h>
int main(void)
{
struct tm tSysTime;
long int secs;
memset(&tSysTime,0,sizeof(tSysTime));
tSysTime.tm_year = 100;
tSysTime.tm_mon = 0;
tSysTime.tm_mday = 1;
tSysTime.tm_hour = 0;
tSysTime.tm_min = 0;
tSysTime.tm_sec = 0;
secs = 946684800 - mktime(&tSysTime);
printf("[main] time zone %ld\n",secs);
return 0;
}
Example runs
$ TZ=Asia/Singapore tzoff
[main] time zone 28800
$ TZ=US/Pacific tzoff
[main] time zone -28800
$ TZ=UTC0 tzoff
[main] time zone 0
$
How did you find 946684800
That's a deep-seated mystery. No, it isn't. I have a pair of programs, strptime and timestamp that helped (plus a casual use of bc).
I live in the 'US/Pacific' (officially, America/Los_Angeles, but I don't like that name much — I live a lot closer to San Francisco) time zone (UTC-08:00 in the winter; UTC-07:00 during the summer).
$ strptime '2000-01-01 00:00:00'
946713600 = 2000-01-01 00:00:00
$ timestamp 946713600
946713600 = Sat Jan 01 00:00:00 2000
$ timestamp -Z 946713600
946713600 = Sat Jan 01 00:00:00 2000 -08:00
$ bc <<< '946713600 - 8 * 3600'
946684800
$ timestamp -Z 946684800
946684800 = Fri Dec 31 16:00:00 1999 -08:00
$ TZ=UTC0 timestamp -Z 946684800
946684800 = Sat Jan 01 00:00:00 2000 +00:00
$
If you spend the time working out how, you can probably do that with GNU date.

angularjs convert date format to IST

I want to convert date from 2015-12-02T18:30:00.000+0000 to Wed Dec 02 2015 00:00:00 GMT+0530 (India Standard Time) using angularjs.
you can make use of angular's date filter . The formats are clearly given here
{{'2015-12-02T18:30:00.000+0000' | date:"EEE MMM dd yyyy HH:hh:ss 'GMT'Z '(India Standard Time)'"}}
The above code snippet will give you Thu Dec 03 2015 00:12:00 GMT+0530 (India Standard Time) in the output. that is the time when you calculate from +0000 to a +0530
Here is a working solution
Working fiddle
HTML:
<div ng:app ng:controller="Scoper">
Input: {{v}} <br />
Angular: {{v | date:'EEE MMM dd yyyy HH:mm:ss'}} GMT{{v | date:'+0530' }} (India Standard Time) <br />
</div>
JS
function Scoper($scope) {
var s = "2015-12-02T18:30:00.000+0000";
$scope.v = s;
}

Find the most recent date from an Array

How to find the most recent date from an array like the one below?
Tue Jun 2 17:59:54 GMT+0200 2013
Tue Jun 5 18:00:10 GMT+0200 2013
Tue Jun 1 12:27:14 GMT+0200 2013
Tue Jun 3 17:26:58 GMT+0200 2013
Tue Jun 9 17:27:49 GMT+0200 2013
Tue Jun 1 13:27:39 GMT+0200 2015
Tue Jun 3 12:27:59 GMT+0200 2013
Tue Jun 6 15:27:22 GMT+0200 2014
Tue Jun 2 17:27:30 GMT+0200 2014
Assuming your array is full of AS3 native Date objects, you could simply do this:
array.sortOn("time",Array.DESCENDING);
trace("Most Recent:",array[0]);
You cannot use array.sort (unless you use the Array.NUMERIC flag) because it will sort the string representation of the date. So all your days of the week would then be grouped together instead of the actual date.
If your dates are strings, then you will need to convert them to Date objects prior to sorting:
//assuming your posted array is in a var called 'stringArray'
var dateArray:Array = []; //a new array to hold the converted strings
for(var i:int=0;i<stringArray.length;i++){
dateArray.push(new Date(stringArray[i]));
}
dateArray.sortOn("time",Array.DESCENDING);
trace("Most Recent Date:",dateArray[0]);
To show this in a concrete example, here is your posted dates - copy paste this code to produce the same results:
var arr:Array = new Array(
new Date("Tue Jun 2 17:59:54 GMT+0200 2013"),
new Date("Tue Jun 5 18:00:10 GMT+0200 2013"),
new Date("Tue Jun 1 12:27:14 GMT+0200 2013"),
new Date("Tue Jun 3 17:26:58 GMT+0200 2013"),
new Date("Tue Jun 9 17:27:49 GMT+0200 2013"),
new Date("Tue Jun 1 13:27:39 GMT+0200 2015"),
new Date("Tue Jun 3 12:27:59 GMT+0200 2013"),
new Date("Tue Jun 6 15:27:22 GMT+0200 2014"),
new Date("Tue Jun 2 17:27:30 GMT+0200 2014")
);
arr.sort(Array.DESCENDING);
trace("SORT:");
traceDates();
arr.sortOn("time",Array.DESCENDING);
trace("\nSORT ON:");
traceDates();
function traceDates(){
for(var i:int=0;i<arr.length;i++){
trace(" ",arr[i].fullYear + "-" + arr[i].month + "-" + arr[i].day);
}
}
//OUTPUT:
/*
SORT:
2013-5-3
2013-5-0
2013-5-0
2013-5-6
2013-5-1
2013-5-1
2014-5-1
2015-5-1 //most recent date, second to LAST item in the array
2014-5-5
SORT ON:
2015-5-1 //June 1st is the most recent date (first item in the array)
2014-5-5
2014-5-1
2013-5-0
2013-5-3
2013-5-1
2013-5-1
2013-5-0
2013-5-6
*/
Are they Date objects?
If so, you can compare the time property of each. It will give you the number of milliseconds since Jan 1, 1970. The highest number will be the most recent.
Something along these lines:
var mostRecentDate:Date = dateArray[0];
for(var i:int = 0; i < dateArray.length; i++){
if(dateArray[i].time > mostRecentDate.time){
mostRecentDate = dateArray[i];
}
}
Date objects act like simple Number when it comes to sorting or comparison. All you have to do is treat them like Numbers. So taken from Cadin answer:
dateArray.sort();
var oldestDate:Date = dateArray[0];
Will get you the oldest Date while:
dateArray.sort(Array.DESCENDING);
var mostRecentDate:Date = dateArray[0];
Will get you the most recent one.
For LDMS, this is what I got:
var firstdate:Date = new Date();
var seconddate:Date = new Date();
var thirddate:Date = new Date();
seconddate.time = firstdate.time + 5000000;
thirddate.time = firstdate.time + 50000000;
trace(seconddate > firstdate)//true
trace(firstdate > seconddate)//false
trace(seconddate.time > firstdate.time)//true
var array:Array = [thirddate, firstdate, seconddate];
trace(array)
//Wed Jun 3 03:37:40 GMT-0400 2015,Tue Jun 2 13:44:20 GMT-0400 2015,Tue Jun 2 15:07:40 GMT-0400 2015
array.sort();
trace(array)
//Tue Jun 2 13:44:20 GMT-0400 2015,Tue Jun 2 15:07:40 GMT-0400 2015,Wed Jun 3 03:37:40 GMT-0400 2015
array.sort(Array.DESCENDING);
trace(array)
//Wed Jun 3 03:37:40 GMT-0400 2015,Tue Jun 2 15:07:40 GMT-0400 2015,Tue Jun 2 13:44:20 GMT-0400 2015
Sort the array and grab the first (descending) or last (ascending) element.
Edit: 2 down-votes because I didn't provide an example, or because people don't know you can sort dates? This works:
var dates:Array = [
"Tue Jun 2 17:59:54 GMT+0200 2013",
"Tue Jun 5 18:00:10 GMT+0200 2013",
"Tue Jun 1 12:27:14 GMT+0200 2013",
"Tue Jun 3 17:26:58 GMT+0200 2013",
"Tue Jun 9 17:27:49 GMT+0200 2013",
"Tue Jun 1 13:27:39 GMT+0200 2015",
"Tue Jun 3 12:27:59 GMT+0200 2013",
"Tue Jun 6 15:27:22 GMT+0200 2014",
"Tue Jun 2 17:27:30 GMT+0200 2014"
].map(function(s:String, i:int, a:Array):Date {
return new Date(s);
}).sort(Array.NUMERIC | Array.DESCENDING);
var latest:Date = dates[0]; // Mon Jun 1 07:27:39 GMT-0400 2015
The problem is the OP did not make it clear what kind of data they are working with (strings or Date objects) so the exact solution code is unknown.

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