findsnd.m

function [numdex] = findsnd(y,m,d,h,sndstructure,sndstructure2,sndstructure3)
%%findsnd
    %Function to find the index of a sounding given a specific date and up
    %to three sounding structures to look through.
    %
    %General form: [numdex] = findsnd(y,m,d,h,sndstructure,sndstructure2,sndstructure3)
    %
    %Output:
    %numdex: the index within the structure (sndstructure) where the input date
    %is found.
    %
    %Inputs:
    %y: a 4-digit year
    %m: a 1 or 2-digit month
    %d: a 1 or 2-digit day
    %h: a 1 or 2-digit time
    %sndstructure: a structure of soundings data
    %Up to two additional soundings structures can be input; numdex will
    %contain as many indices as there are soundings, and will display NaN for
    %structures where the date is not present.
    %
    %NOTE: Sounding tables can also be used as input! Just be sure to input
    %as table2struct(table) and be patient as runtime is longer this way.
    %
    %Version date: 4/20/2018
    %Last major revision: 5/31/2017
    %Written by: Daniel Hueholt
    %North Carolina State University
    %Undergraduate Research Assistant at Environment Analytics
    %
try
    dateFull = [y,m,d,h];
catch ME;
    msg = 'Improper input! Time input must include year, month, day and hour.'; %Usually the problem is that the time has been entered wrong, such as missing an hour input
    error(msg);
end

switch nargin
    case 7 %All possible inputs
        disp('Three soundings structures were entered.')
        %3 for loops to find the indices in all structures
        for k = 1:length(sndstructure)
            if isequal(sndstructure(k).valid_date_num,dateFull)==1 %Looking for the datenumber which matches the input datenumber
                disp(['Sounding number in first structure is ' num2str(k)]) %Where the if statement is true, the counter is the index corresponding to the correct soundings entry
                numdex(1) = k; %Index in first structure is first entry in output array
                break %Move to the next loop as soon as the index is found
            end
        end
        for k2 = 1:length(sndstructure2)
            try %Just in case
                if isequal(sndstructure2(k2).valid_date_num,dateFull)==1
                    disp(['Sounding number in second structure is ' num2str(k2)])
                    numdex(2) = k2; %Index in second structure is second entry in output array
                    break
                end
            catch ME; %#ok
                continue
            end
        end
        for k3 = 1:length(sndstructure3)
            try
                if isequal(sndstructure3(k3).valid_date_num,dateFull)==1
                    disp(['Sounding number in third structure is ' num2str(k3)])
                    numdex(3) = k3; %Index in third structure is third entry in output array
                    break
                end
            catch ME; %#ok
                continue
            end
        end
    case 6
        disp('Two soundings structures were entered.')
        %2 for loops to find the indices in all structures
        for k = 1:length(sndstructure)
            if isequal(sndstructure(k).valid_date_num,dateFull)==1
                disp(['Sounding number in first structure is ' num2str(k)])
                numdex(1) = k; %Index in first structure is first entry in output array
                break
            end
        end
        for k2 = 1:length(sndstructure2)
            try
                if isequal(sndstructure2(k2).valid_date_num,dateFull)==1
                    disp(['Sounding number in second structure is ' num2str(k2)])
                    numdex(2) = k2; %Index in second structure is second entry in output array
                    break
                end
            catch ME; %#ok
                continue
            end
        end
    case 5
        for k = 1:length(sndstructure)
            if isequal(sndstructure(k).valid_date_num,dateFull)==1
                disp(['Sounding number is ' num2str(k)])
                numdex = k; %Index is output
                break
            end
        end
    otherwise %Less than 5 entries implies that either several time entries were left off or there was no sounding data structure specified
        msg = 'Improper input! Please check syntax and try again.'; %either way
        error(msg) %it's very wrong
end

if ~exist('numdex','var') %If after searching the structures there still is no numdex, then the input time was not found in the structure(s)
    numdex = NaN;
    msg = 'The input time was not found in the structure(s)!';
    disp(msg)
end

numdex(numdex==0) = NaN; %Any 0 entries should be NaN to be clearer that the index is not present in the respective structure

disp(['Input time: ' num2str(dateFull)]) %Display the datenumber to make it easy for the user to know what they entered

end