...
Note that the meta-data for each field is taken from the first field in each subtraction; "step9 minus step6" returns a field with meta-data from step9, so be aware of this. Macro has functions for setting GRIB meta-data if you need to change it in order to correctly describe the new data.
Dates in Macro
Macro has specific date-handling abilties. Dates are a built-in data type which in fact describe both a date and a time.
Defining dates
You can create date variables in a number of ways:
- yyyy-mm-dd
- yyyy-DDD (DDD is a 3-digit Julian day, e.g. 365 is 31st December in non-leap years)
These will have the time set to 00:00. A different time can be added by adding
- HH:MM
- HH:MM:SS
Create a new Macro icon, rename it to dates and define a date:
Code Block | ||
---|---|---|
| ||
d = 2015-03-11
print(type(d))
print(d) |
Try adding a time:
Code Block |
---|
d = 2015-03-11 09:00 |
Converting numbers into dates
The date()
function converts numbers into dates using the same syntax that MARS understands. For example:
- d1 = date(20150105)
- today = date(0)
- yesterday = date(-1)
Again, the time will be 00:00 unless we add it. We can consider the time to be a fraction of a day:
- midday = date(20150105.5)