MATLAB: Function for day of the year

days of the yearfunctionif else

How do I write a function that responds the days of the year when given a certain date? For example, January 7th, 2017 would respond 7 as that is the 7th day of the year. (This is also accounting for leap years.)

Best Answer

Introduced in R2014b

>> day( datetime('07-Jan-2017', 'InputFormat', 'dd-MMM-yyyy' ), 'dayofyear' )
ans =
     7

"accounting for leap years" If not, shame on The MathWorks!

>> day( datetime('01-Mar-2017', 'InputFormat', 'dd-MMM-yyyy' ), 'dayofyear' )
ans =
    60
>> day( datetime('01-Mar-2016', 'InputFormat', 'dd-MMM-yyyy' ), 'dayofyear' )
ans =
    61

Related Solutions

MATLAB: How do a get a specific day of the year

The problem is caused by this line:

[year month day] = ymd(date);

When you have variables named year, month, and day, then you can no longer use the MATLAB functions of the same names. This is known as shadowing the function. So when you call day(datetime(...)), you are telling MATLAB that you want to index into your variable day using a datetime object, which does not make much sense and so MATLAB throws an error.

Solution: change the names of those variables, and clear your workspace (or restart MATLAB).

In future, always check if a name is used, before using it for any variable, e.g.:

which day -all

MATLAB: Function that transforms years into days

Like this?

function numDay = year2days(year)
  numDay = days(datetime(year,12,31)-datetime(year,1,1))+1;
end

The following is one example:

>> year2days(2000)
ans =
 366

Best Answer

Related Solutions

MATLAB: How do a get a specific day of the year

MATLAB: Function that transforms years into days

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