How to get last Sunday's date? - date

I need to show last Sunday's date in a cell for a weekly report that I'm creating on google sheets. I've been googling to find a solution and the closest I found is this:
=TODAY()+(7-WEEKDAY(TODAY(),3))
But this gives next Monday's date. Any idea how to modify this to show last Sunday's date? Alternately, do you have another way to solve this problem?

The formula you're looking for would be:
=DATE(YY, MM, DD) - (WEEKDAY(DATE(YY, MM, DD)) - 1) - 7
// OR
=TODAY() - (WEEKDAY(TODAY()) - 1) - 7
Depending on what you take to be "last Sunday," you can simplify/factor this:
If you take "last Sunday" to mean, "the Sunday which has most recently happened:"
=DATE(A2,B2,C2) - WEEKDAY(DATE(A2,B2,C2)) + 1
If you take "last Sunday" to mean, "the Sunday which took place during the previous week:"
=DATE(A4,B4,C4) - WEEKDAY(DATE(A4,B4,C4)) - 6
Working through it:
=TODAY() - (WEEKDAY(TODAY()) - 1) - 7
TODAY()
// get today's date, ie. 22/11/2019
WEEKDAY(TODAY())
// get the current day of the week, ie. 6 (friday)
-
// take the first date and subtract that to rewind through the week,
// ie. 16/11/2019 (last saturday, since saturday is 0)
- 1
// rewind back one less than the entire week
// ie. 17/11/2019 (this sunday)
- 7
// rewind back to the sunday before this
// sunday, ie. 10/11/2019
Hopefully this explanation explains what the numbers at the end are doing. + 1 takes you from the Saturday of last week to the Sunday of the current week (what I would call "this Sunday"), and - 6 takes you back through last week to what I would call "last Sunday."
See here:

try:
=ARRAYFORMULA(TO_DATE(FILTER(ROW(INDIRECT(VALUE(TODAY()-6)&":"&VALUE(TODAY()))),
TEXT(ROW(INDIRECT(VALUE(TODAY()-6)&":"&VALUE(TODAY()))), "ddd")="Sun")))
if today is Sunday and you want still the last Sunday then:
=ARRAYFORMULA(IF(TEXT(TODAY(), "ddd")="Sun", TODAY()-6,
TO_DATE(FILTER(ROW(INDIRECT(VALUE(TODAY()-6)&":"&VALUE(TODAY()))),
TEXT(ROW(INDIRECT(VALUE(TODAY()-6)&":"&VALUE(TODAY()))), "ddd")="Sun"))))

Using monday as 1 index, this will return the previous sunday or today if it is sunday
=if((7-WEEKDAY(today(),2))>0,today()-(7-(7-WEEKDAY(today(),2))),today()+(7-WEEKDAY(today(),2)))
One can select for other days of the week by changing the number "7" directly before "-WEEKDAY(today(),2)" in the three places that pattern exists.

Related

GSheets - Time between date and now()

Trying different things and combos, but can't get it right. Times and dates always get me.
I'm simply trying to compare now() and a date/time and show "in 2 days 6 hrs 30 mins" or "3 days 1 hr 20 mins ago" and I'm guessing someone has done this already?
So, let's say the date in column A is 2023-01-24 10:00 and now it is 2023-01-25 11:05, then Col B should say "1 day 1 hr 5 mins ago"
I've tried duration(), date/time formatting the cell, days(..), but I can't find something that works reliably.
Another thing you could try:
=INT(NOW()-A1)&" d "&TEXT(NOW()-A1,"h \hr m \min a\go")
=NOW()-A1 will actually calculate the difference between Now and that time, BUT consider that the time is updated only when you make a change, it's not a countdown second by second. You can add an updater per minute but not more than that. Go to File - Settings and set On change and every minute:
If you need a specific format like that you mentioned you should then do calculations to add them. If you only need days, hours, minutes and seconds, you can do the next checkings and concatenations:
=LAMBDA(dif,
IF(INT(dif),INT(dif)&" days ","")
&IF(HOUR(dif),HOUR(dif)&" hours ")
&IF(MINUTE(dif),MINUTE(dif)&" minutes ")
&IF(SECOND(dif),SECOND(dif)&" seconds")&" ago")
(Now()-A1)
please try:
=TRIM(LAMBDA(y,IF(NOW()-A1<1,"0 days",IF(y=1,y&" "&"day",y&" "&"days")))(DATEDIF(A1,NOW(),"D"))&" "&
LAMBDA(y,IF(y=1,y&" "&"hr",y&" "&"hrs"))(HOUR(NOW()-A1))&" "&
LAMBDA(y,IF(y=1,y&" "&"min",y&" "&"mins"))(MINUTE(NOW()-A1))&" ago")
try:
=INDEX(IF(ISDATE_STRICT(A2:A), TRIM(FLATTEN(QUERY(TRANSPOSE(
IFERROR(LAMBDA(a, LAMBDA(x, IF(x=0,,IF(x>1, x&a&"s", x&a)))
(DATEDIF(A2:A, NOW(), {"Y", "YM", "MD"})))({" year", " month", " day"}))),,9^9))), ))

Check the weekday in Swift

I have a nice idea of an app and I am new in swift. The app is about a week schedule, you can add some things you have to do in a schedule.For example, on Monday you have to clean the bathroom and get milk. You can add this two things to the day plan for Monday. But my really problem is that I want the app to show the schedule of the current day when you open it. I don't have any idea how to check the day of the week so the schedule when you open the app is for the current day. It will be easy if I add a label named dayname on the top and it should show the name of the current weekday !!
I did not try it, but this post seems to be clear with enough details and examples dealing with dates in Swift. Check it HERE
here is an example from the same source working with NSDateComponents weekday property:
// First Saturday of March 2015, US/Eastern
let firstSaturdayMarch2015DateComponents = NSDateComponents()
firstSaturdayMarch2015DateComponents.year = 2015
firstSaturdayMarch2015DateComponents.month = 3
firstSaturdayMarch2015DateComponents.weekday = 7
firstSaturdayMarch2015DateComponents.weekdayOrdinal = 1
firstSaturdayMarch2015DateComponents.hour = 11
firstSaturdayMarch2015DateComponents.minute = 0
firstSaturdayMarch2015DateComponents.timeZone = NSTimeZone(name: "US/Eastern")
// On my system (US/Eastern time zone), the result for the line below is
// "Mar 7, 2015, 11:00 AM"
let firstSaturdayMarch2015Date = userCalendar.dateFromComponents(firstSaturdayMarch2015DateComponents)!
It says :
NSDateComponents‘ weekday property lets you specify a weekday
numerically. In Cocoa’s Gregorian calendar, the first day is Sunday,
and is represented by the value 1. Monday is represented by 2,
Tuesday is represented by 3, all the way to Saturday, which is
represented by 7.

nvd3 (d3.js) date format returns incorrect month

My data looks like this:
[{ x="2013-06-01", y=3}, { x="2013-07-01", y=7 }, { x="2013-08-01", y=3 }]
Chart x-axis is formatted as so:
chart.xAxis
.axisLabel('Date')
.tickFormat(function(d) { return d3.time.format('%b %Y')(new Date(d)); })
;
%b returns May, Jun, July respectively for the dates 2013-06-01, 2013-07-01, 2013-08-01
Why is it returning the previous month, and how can I fix it?
EDIT: If the date is formatted as 2013-06-02, it will return the correct month... does someone know what is happening to cause this?
#Amelia is correct it's because of timezone difference and because Date defaults to 24:00:00 if you don't specify a time. So, in case of EDT, which is -4:00, you lose 4 hours which puts you in the previous day (May 31 2013 20:00:00) and because the days in your dates are 01, this puts you in the previous month.
To bypass this you could append a time to your date if that is allowable in your case.
chart.xAxis
.axisLabel('Date')
.tickFormat(function(d) {
d = d.split('-')
// Create new date by using new Date(year, month, day, hour, second, ms)
// Subtracting 1 is necessary since Javascript months are 0 - 11.
return d3.time.format('%b %Y')(new Date(d[0], +d[1] - 1, d[2], 12, 0, 0));
});
Here is a working Fiddle

Cocoa Touch: Laying out dates on a month-view calendar

I'm aware that there are several Cocoa Touch/iPhone calendar implementations available online, but for certain reasons I'm trying to create my own. I'm running into an issue where the code that I use to lay out the dates (which I represent as instances of UIView placed as subviews into another UIView) is messing up in December.
Currently, what I do is decompose the date into an instance of NSDateComponents, then get the week and weekday properties of the components to figure out the X and Y "positions" of the date view, respectively. I can offset the X position by the week property for the first day of the month I'm laying out.
Brief example: the first day of August 2009 falls on a Saturday, and its date components' week property is 31 (using a Gregorian calendar). Therefore its Y position is 6 and its X position is 0, and the X offset I'll be using is 31. So I can take the second day of August, which is a Sunday, and determine that its X position is 0 and its Y position is week - 31 = 32 - 31 = 1. This way I can lay out a zero-indexed grid of date views for the month of August, and it all goes swimmingly...
...until I try to do the same for December. In December of 2009, apparently the week property wraps to 1 on the 27th (a Sunday), meaning that I wind up trying to place the 27th through the 31st at Y positions -48 or so.
My question is twofold: why does the week property wrap partway into the last month of the year? Is it indexed at the last Sunday of the previous year, rather than the first day of the year? And second, is there a better way to lay out a date grid like this (using other components from an NSDateComponents instance, or anything else I can get from an NSDate and an NSCalendar), or do I just have to add a check for the "last week of year" condition?
The last few days in December start to belong to week 1 of the next year. (see here)
Instead of using the week property to calculate the weekday positions, I'd just start with Y=0 and then increase it after each Saturday (if your week starts on Sundays)
int x = <calculate x based on the weekday of the 1st of the month>
int y = 0
for (days in month) {
<add subview for this day>
x += xOffset
if (currentWeekday == saturday) {
x = 0
y += yOffset
}
}
P.S.: I'd probably look at the current locale to determine the first weekday:
NSLocale *locale = [NSLocale currentLocale];
NSCalendar *calendar = [locale objectForKey:NSLocaleCalendar];
NSUInteger firstWeekday = [calendar firstWeekday];
I probably wouldn't use weeks in my calculation. You need to lay out the days in rows of 7, which of course we know conceptually as weeks. Practically you should be able to get away just knowing the day of the year and doing a modulus.
Say the year starts on Sunday (column 1) and you want know the position of the 100th day. Well 100 / 7 = 14 with a remainder. So it is in the 14th row. Then do a mod 100 % 7 = 2. So it falls on a Monday (in my example).

Unix gettimeofday() - compatible algorithm for determining week within month?

If I've got a time_t value from gettimeofday() or compatible in a Unix environment (e.g., Linux, BSD), is there a compact algorithm available that would be able to tell me the corresponding week number within the month?
Ideally the return value would work in similar to the way %W behaves in strftime() , except giving the week within the month rather than the week within the year.
I think Java has a W formatting token that does something more or less like what I'm asking.
[Everything below written after answers were posted by David Nehme, Branan, and Sparr.]
I realized that to return this result in a similar way to %W, we want to count the number of Mondays that have occurred in the month so far. If that number is zero, then 0 should be returned.
Thanks to David Nehme and Branan in particular for their solutions which started things on the right track. The bit of code returning [using Branan's variable names] ((ts->mday - 1) / 7) tells the number of complete weeks that have occurred before the current day.
However, if we're counting the number of Mondays that have occurred so far, then we want to count the number of integral weeks, including today, then consider if the fractional week left over also contains any Mondays.
To figure out whether the fractional week left after taking out the whole weeks contains a Monday, we need to consider ts->mday % 7 and compare it to the day of the week, ts->wday. This is easy to see if you write out the combinations, but if we insure the day is not Sunday (wday > 0), then anytime ts->wday <= (ts->mday % 7) we need to increment the count of Mondays by 1. This comes from considering the number of days since the start of the month, and whether, based on the current day of the week within the the first fractional week, the fractional week contains a Monday.
So I would rewrite Branan's return statement as follows:
return (ts->tm_mday / 7) + ((ts->tm_wday > 0) && (ts->tm_wday <= (ts->tm_mday % 7)));
If you define the first week to be days 1-7 of the month, the second week days 8-14, ... then the following code will work.
int week_of_month( const time_t *my_time)
{
struct tm *timeinfo;
timeinfo =localtime(my_time);
return 1 + (timeinfo->tm_mday-1) / 7;
}
Assuming your first week is week 1:
int getWeekOfMonth()
{
time_t my_time;
struct tm *ts;
my_time = time(NULL);
ts = localtime(&my_time);
return ((ts->tm_mday -1) / 7) + 1;
}
For 0-index, drop the +1 in the return statement.
Consider this pseudo-code, since I am writing it in mostly C syntax but pretending I can borrow functionality from other languages (string->int assignment, string->time conversion). Adapt or expand for your language of choice.
int week_num_in_month(time_t timestamp) {
int first_weekday_of_month, day_of_month;
day_of_month = strftime(timestamp,"%d");
first_weekday_of_month = strftime(timefstr(strftime(timestamp,"%d/%m/01")),"%w");
return (day_of_month + first_weekday_of_month - 1 ) / 7 + 1;
}
Obviously I am assuming that you want to handle weeks of the month the way the standard time functions handle weeks of the year, as opposed to just days 1-7, 8-13, etc.