time

问题 I am trying to calculate sleep duration, in hours, from two times self-reported in a diary. I have the bed and wake times in 24-hour format (for bedtimes, for instance, "23:00" is 11PM, "0:00" is midnight, "1:00" is 1AM; for wake times, "9:00" is 9AM). I thought the difftime function would be good to extract the sleep duration, but I am running into an issue with some of the cases. df$duration2<-difftime(df$Waketime2, df$Bedtime2, units="hours") In running the syntax above, it correctly

问题 I am trying to calculate sleep duration, in hours, from two times self-reported in a diary. I have the bed and wake times in 24-hour format (for bedtimes, for instance, "23:00" is 11PM, "0:00" is midnight, "1:00" is 1AM; for wake times, "9:00" is 9AM). I thought the difftime function would be good to extract the sleep duration, but I am running into an issue with some of the cases. df$duration2<-difftime(df$Waketime2, df$Bedtime2, units="hours") In running the syntax above, it correctly

问题 I'm currently doing some work in an application domain that uses time values greater than 24:00 to represent times after midnight that are still associated with the previous day's details. For instance, it might use 25:15 on Monday to represent 1:15 AM on Tuesday, since from a domain standpoint, this value is still associated with Monday's data. This type of time usage is briefly mentioned in the Wikipedia article for the 24-hour clock: Time-of-day notations beyond 24:00 (such as 24:01 or 25

问题 I need to convert a date in yyyy-mm-dd like 2011-12-30 to UTC using only javascript. How? 回答1: var utc = new Date('2011-12-30').toUTCString(); jsFiddle. 回答2: If you're having problems getting the other listed solution to work in firefox or safari you can use: http://www.datejs.com/ myDate = new Date.parse("2011-12-30") myUTCDate = Date.UTC(myDate.getFullYear(), myDate.getMonth(), myDate.getDate(), myDate.getHours(), myDate.getMinutes(), myDate.getSeconds(), myDate.getMilliseconds()); Voila!!

问题 I need to convert a date in yyyy-mm-dd like 2011-12-30 to UTC using only javascript. How? 回答1: var utc = new Date('2011-12-30').toUTCString(); jsFiddle. 回答2: If you're having problems getting the other listed solution to work in firefox or safari you can use: http://www.datejs.com/ myDate = new Date.parse("2011-12-30") myUTCDate = Date.UTC(myDate.getFullYear(), myDate.getMonth(), myDate.getDate(), myDate.getHours(), myDate.getMinutes(), myDate.getSeconds(), myDate.getMilliseconds()); Voila!!

问题 I would like my online shop to be deactivated or activated for a certain period of time. When the shop is deactivated, you can see the products, but can't put them in the shopping cart. If you already have things in your shopping cart, you can't checkout and pay. Despite all this, you can see the products, but you can't buy them. Shop time would be as follows: Online: Monday to Sunday from 12 am to 22 pm Offline: the remaining time is to be deactivated Is that possible? I've already found a

问题 I would like my online shop to be deactivated or activated for a certain period of time. When the shop is deactivated, you can see the products, but can't put them in the shopping cart. If you already have things in your shopping cart, you can't checkout and pay. Despite all this, you can see the products, but you can't buy them. Shop time would be as follows: Online: Monday to Sunday from 12 am to 22 pm Offline: the remaining time is to be deactivated Is that possible? I've already found a

问题 I am writing an app that has a time slot booking system. The users can be in different timezones, thus I need to store the values in the database in UTC time. I was wondering how UTC_TIMESTAMP() is calculated in MySQL. Is it reliable? If the server timezone is in an area with daylight savings will UTC_TIMESTAMP() always behave correctly, even during time changes due to daylight savings? 回答1: UTC is always +0:00 - it ignores daylight savings, regardless of whether or not it is in effect. In

问题 This is a question similar to this one. I'm really tempted to store datetimes in my app as local time rather than as UTC (which is considered a best practice). In the app I have a number of events happening, each assigned to a given location. Always when I display them to the user, I want to show the local time of the event. I.e.: ==================================================================================== Event time (with TZ) | As UTC | As local time | To be displayed | =============

问题 This is a question similar to this one. I'm really tempted to store datetimes in my app as local time rather than as UTC (which is considered a best practice). In the app I have a number of events happening, each assigned to a given location. Always when I display them to the user, I want to show the local time of the event. I.e.: ==================================================================================== Event time (with TZ) | As UTC | As local time | To be displayed | =============