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Days Since January 1 2020

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Last Updated: 04 October 2020

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General | Latest Info

R provides several options for dealing with date and date / time data. Builtin as. The Date function handles dates; contribute library chron handles dates and times, but does not control for time zones; and POSIXct and POSIXlt classes allow for dates and times with control for time zones. The general rule for date / time data in R is to use the simplest technique possible. Thus, for date only data, as. A date will usually be the best choice. If you need to handle dates and times, without timezone information, chron library is a good choice; POSIX classes are especially useful when timezone manipulation is important. Also, don't overlook various as. Functions for converting between different date types when necessary. Except for POSIXlt class, dates are stored internally as the number of days or seconds from some reference date. Thus, dates in R will generally have numeric mode, and the class function can be used to find way they are actually being store. Posixlt class stores date / time values as a list of components, making it easy to extract these parts. To get the current date, system Date function will return date object which can be converted to a different class if necessary. The following subsections will describe different types of date values in more detail. As. The Date function allows a variety of input formats through format = argument. The default format is four digit year, followed by month, then day, separated by either dashes or slashes. The following example shows some examples of dates which as. Date will be accepted by default: if your input dates are not in standard format, format string can be composed using elements shown in Table. The following examples show some ways that this can be used to extract components of dates, weekdays, months, days or quarters functions can be used. For example, to find the day of week on which some famous statisticians were born, we can look at the result of weekdays function: chron function converts dates and times to chron objects. Dates and times are provided to chron function as separate values, so some preprocessing may be necessary to prepare input date / times for chron function. When using character values, default format for dates is decimal month value followed by decimal day value followed by year, using slash as separator. Alternative formats can be provided by using codes shown in the table. Alternatively, dates can be specified by numeric value, representing the number of days since January 1 1970. To input dates stored as day of year, origin = argument can be used to interpret numeric dates relative to different date. The default format for times consists of hour,sss minutes and seconds, separated by colons. Alternative formats can use codes on the table.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Number of days in 2020

This site provides an online date calculator to help you find the difference in number of days between any two calendar dates. Simply enter start and end date to calculate the duration of any event. You can also use this tool to determine how many days have passed since your birthday, or measure the amount of time until your baby's due date. Calculations use the Gregorian calendar, which was created in 1582 and later adopted in 1752 by Britain and the eastern part of what is now the United States. For best results, use dates after 1752 or verify any data if you are doing genealogy research. Historical calendars have many variations, including the ancient Roman calendar and Julian calendar. Leap years are used to match the calendar year with the astronomical year. If you re trying to figure out the date that occur in X Days from today, switch to the Days From Now calculator instead.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Date calculator

The Gregorian Calendar is the most prevalently used Calendar today. Within this calendar, standard year consists of 365 days with leap Day being introduced to the month of February during leap Year. The months of April, June, September, and November have 30 days, while the rest have 31 days except for February, which has 28 days in standard Year, and 29 in leap Year. The Gregorian Calendar is a reformed version of the Julian Calendar, which was itself a modification of the ancient Roman Calendar. The ancient Roman Calendar was believed to be an observational lunar Calendar, based on cycles of the moon's phases. The Romans were then believed to have adopted a 10 - month Calendar with 304 days, leaving the remaining 50 or so days as unorganized winter. This calendar allows summer and winter months to become completely misplaced, leading to the adoption of more accurate calendars. The Republican Calendar later used by Rome follows Greek calendars in its assumptions of 29. 5 days in lunar cycle, and 12. 5 synodic months in the solar Year, which align every fourth year upon addition of intercalary months of January and February. From this point, many attempts were made to align the Republican Calendar with the solar Year, including the addition of an extra month to certain years to supplant lack of days in a particular year. In 46 BC, calendar was further reformed by Julius Caesar, introducing an algorithm that removed dependence on calendars from observation of New moon. In order to accomplish this, Caesar inserted an additional 10 days into the Republican Calendar, making the total number of days in Year 365. He also added the intercalation of leap Day every fourth Year, all in an attempt to further synchronize the Roman Calendar with the solar Year. Despite all efforts, Julian Calendar still requires further reform, since the calendar drifts with respect to equinoxes and solstices by approximately 11 minutes per year. By 1582, this resulted in a difference of 10 days from what was expect. Pope Gregory XIII addrest this by essentially skipping 10 days in date, making the day after October 4 1582, October 15. Adjustment was also made to the algorithm of the Julian Calendar that changed which century years would be considered leap years. Under the Gregorian Calendar, century years not divisible by 400 would not be leap years. These changes reduce error from 1 day in 128 years, to 1 day in 3 030 years with respect to the current value of mean solar year. Adoption of the Gregorian Calendar occurred slowly over period of centuries, and despite many proposals to further reform the Calendar, Gregorian Calendar still prevails as the most commonly used dating system worldwide. A holiday is a day that, either by custom or by law, is set aside such that regular activities like going to work or school are suspend, or at least reduced.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Programming routines

Table 1: SAS internal values for selected dates.

DateSAS Internal Value
January 1, 19600
January 3, 19602
December 31, 1959-1
January 1, 1959-365
January 1, 1961366
January 1, 19631096

Before reading this tutorial, you may wish to review SAS Date Formats and Informats and SAS Date, Time, and Datetime Values. Dates, times, and Date - times are commonly used variable types in research. In SAS, dates and times are considered numeric variables, but they have several special properties to be aware of. Regardless of how researchers record dates or times in their dataset, SAS internally records datetime variables as integers. This helps to simplify computations when computing differences between dates. Sas Time Values are stored internally as the number of seconds between midnight of the current DAY and another time value. Sas Datetime Values store internally as number of seconds between midnight, January 1 1960, and specifies date and time. Sas Date Values are stored internally as number of days between January 1, 1960, and specified date. Dates after January 1 1960, are stored as positive numbers; Dates before January 1 1960, are stored as negative numbers. By default, SAS Date and Time variables are printed using SAS internal Values, rather than human - readable Date Format. However, dates can be displayed using any chosen format by setting Format in Data step or proc step. In this tutorial, we show how to compute new variables from dates and times using two major types of date functions: extraction - type functions and computation - type functions. Date extraction functions are used to extract portion of date from date variable. Year - give number or variable representing date or datetime, returns YEAR. Qtr - give number or variable representing date or datetime, returns quarter. Month - give number or variable representing date or datetime, return MONTH. Day - give number or variable representing date or datetime, returns DAY. Weekday - give number or variable representing date or datetime, returns day of week. Date creation functions construct new date or Datetime variables based on their inputs. Mdy - give numbers or variables representing MONTH, DAY, and YEAR, creating a new date variable. Date computation functions carry out arithmetic operations on dates; for example, computing elapsed time between two dates. Datdif - give two SAS dates or datetimes, compute the difference between dates in days. Yrdif - give two SAS dates or datetimes, compute the difference between dates in years. Note that DATDIF and YRDIF functions require special argument basis argument. Basis arguments determine how date arithmetic is carried out. Specifically, it determines the number of days that should be used to characterize period of time in MONTH or YEAR. In SAS 9. 3, there are five possible options that can be used which are indicated by the following character strings: give SAS Date value, WEEKDAY function extracts DAY of week from SAS Date value as number from 1 - 7.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

Table 2: Valid character strings for basis argument in DATDIF and YRDIF functions.

Character StringMeaning
'30/360'Specifies a 30 day month and a 360 day year, regardless of the actual number of calendar days in a given month or year.
'ACT/ACT' or 'Actual'Uses the actual number of days or years between dates.
'ACT/360'Uses the actual number of days in a particular month, and 360 days as the number of days in a year (regardless of the actual number of days in a given year.)
'ACT/365'Uses the actual number of days in a particular month, and 365 days as the number of days in a year (regardless of the actual number of days in a given year.)
'AGE'Valid for YRDIF function only. Specifies that a person's age will be computed. This is the default option for YRDIF.
* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

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