time series with time lags

Question

YH 2020-9-22

回答： Ameer Hamza 2020-9-22

Hallo every one,

I have an array called sl(24000*1) which represents daily sea level measurements.

I have another array idx(34*1) represents the indexes of the annual maximum of a river discharg near the above mentioned gauge station

now I have to make a new time series of sea levels corresponding to the annual maximum of the river discharge time series

with time lags (-3 to +3) days, that means for each idx, i should find the coressponding value in sl with a range of -3 to +3 days.

for i = 1: size(idx,1)
 out = sl(idx(i)-3:idx(i)+3);
end

this gives me only one value with its time lags

can some one tell me where exactly I am doing wrong?

Thanks in Advance!

Khaled Hamed 2020-9-22

out(i,:) = sl(idx(i)-3:idx(i)+3)';

Answer 1

Ameer Hamza 2020-9-22

This will create a single vector with all the required values

idx_all = arrayfun(@(x) {x-3:x+3}, idx);
out = sl([idx_all{:}])