Using ismember in an if statement?

Hi,

I have data with dates/position for 10 GPS stations. Each of the GPS stations has a date range, with some values missing and not all date ranges are the same, therefore I cannot apply equations across the arrays, such as averaging all 10 positions for each day.

So far I have created a matrix (NewDate - 10 stations) using a date set (Date) that is as wide as the largest date set from a GPS station and used ismember to create rows of 1s and 0s and multiplied them by 'Date' to place zeros in the missing dates for each GPS station.

Date=[735215:736744];
NewDate=zeros(1530, 10);

for i=1:numel(StationName) 
    NewDate(:,i:i)=ismember(Date, StructureName((i)).Date);
    StructureName((i)).NewRow= NewDate(:,i:i).*Date;
end

What I am trying to get at.. is can I use an if statement to put position data into this structure with 0s where data is missing?

• if date exists, then put position{1} in row 1
• if the date is zero, place the next position in the spot where date is not a zero.

I hope that explanation wasn't too confusing... Thanks!