How to use if/then to assign a year to a set of dates?

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I would like to add a new vector called "school_year" that assigns a year to each point. In this case, a school year will be considered as starting August 1 and ending the following year in July 31st. For example, August 1st, 2000 - July 31st, 2001 should be assigned as school year 2001.
I want to use an if/then based on the month/year to generate the "school_year" value for each data point. A hint I have been given in this assignment is to use an if/then statement, for example, if it is after July, then what?
So in this table, there would be a new column called school_year that should read the following:
2001
2001
2001
2001
2002
2002
2002
2002
2002
table_a = readtable('Data1.xlsx')
table_a = 9×4 table
month day year students _____ ___ ____ ________ 8 7 2000 12 9 8 2000 14 9 9 2000 13 3 11 2001 11 8 3 2001 17 12 15 2001 14 2 2 2002 10 5 1 2002 9 7 3 2002 16

Risposta accettata

Les Beckham
Les Beckham il 6 Feb 2023
Modificato: Les Beckham il 6 Feb 2023
table_a = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1286455/Data1.xlsx')
table_a = 9×4 table
month day year students _____ ___ ____ ________ 8 7 2000 12 9 8 2000 14 9 9 2000 13 3 11 2001 11 8 3 2001 17 12 15 2001 14 2 2 2002 10 5 1 2002 9 7 3 2002 16
table_a.date = datetime(table_a.year, table_a.month, table_a.day)
table_a = 9×5 table
month day year students date _____ ___ ____ ________ ___________ 8 7 2000 12 07-Aug-2000 9 8 2000 14 08-Sep-2000 9 9 2000 13 09-Sep-2000 3 11 2001 11 11-Mar-2001 8 3 2001 17 03-Aug-2001 12 15 2001 14 15-Dec-2001 2 2 2002 10 02-Feb-2002 5 1 2002 9 01-May-2002 7 3 2002 16 03-Jul-2002
schoolyear = zeros(size(table_a.date));
schoolyear(isbetween(table_a.date, '01-Aug-2000', '31-Jul-2001')) = 2001;
schoolyear(isbetween(table_a.date, '01-Aug-2001', '31-Jul-2002')) = 2002;
table_a.schoolyear = schoolyear
table_a = 9×6 table
month day year students date schoolyear _____ ___ ____ ________ ___________ __________ 8 7 2000 12 07-Aug-2000 2001 9 8 2000 14 08-Sep-2000 2001 9 9 2000 13 09-Sep-2000 2001 3 11 2001 11 11-Mar-2001 2001 8 3 2001 17 03-Aug-2001 2002 12 15 2001 14 15-Dec-2001 2002 2 2 2002 10 02-Feb-2002 2002 5 1 2002 9 01-May-2002 2002 7 3 2002 16 03-Jul-2002 2002
If you have more data than just this small sample, the hard-coded statements above that set the schoolyear could be replaced with code like this:
found_years = unique(table_a.year);
for i = 1:numel(found_years)
schoolyear(isbetween(table_a.date, sprintf('01-Aug-%d', found_years(i)-1), sprintf('31-Jul-%d', found_years(i)))) = found_years(i);
end
schoolyear
schoolyear = 9×1
2001 2001 2001 2001 2002 2002 2002 2002 2002
  6 Commenti
Macy
Macy il 7 Feb 2023
Thank you @Les Beckham for explaining that in depth, I learned many new functions, and I will include both methods in my assignment!

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Più risposte (1)

John D'Errico
John D'Errico il 6 Feb 2023
Modificato: John D'Errico il 6 Feb 2023
Easy peasy. :)
data = [8 7 2000 12
9 8 2000 14
9 9 2000 13
3 11 2001 11
8 3 2001 17
12 15 2001 14
2 2 2002 10
5 1 2002 9
7 3 2002 16];
You have year as the third column there. I'll call it trueyear. Just create a variable, call it schoolyear.
schoolyear = trueyear + (month >= 8);
Will that work? Of course. The school year is ALWAYS the same as the trueyear when you are in the first part of the year, so between January 1 and July 31. Once the month goes into month #8, this adds 1 to the trueyear.
There is no if statement required.
  6 Commenti

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