Extracting corresponding timestamp in two tables of different sizes.

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DD_2023
DD_2023 2023-5-26
回答： Peter Perkins 2023-6-5
I have two versions of one dataset. A final processed version that includes timestamps with hours and minutes (the seconds got lost early in the processing), and a raw version that retains the original datestamp with seconds. I would like to be able to extract the timestamp with seconds, and match it to the final data.
I currently have the data as two tables and have tried to extract the locations based on where variables that appear in both tables match (using ismember), but it doesn't seem to be finding the right timestamps.
x = ismember(old.Var1, new.Var1) & ismember(old.Var2, new.Var2) & ismember(old.Var3, new.Var3);
y = old.Timestamp(x);
Ay advice would be appreciated!
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DD_2023
DD_2023 2023-5-30
Thanks for the suggestion, I believe I still have the issue that my dataset without seconds has multiple datapoints per minute. So there's no way to ensure the correct timestamps, and corresponding data, get matched.

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Peter Perkins
Peter Perkins 2023-6-5
The times are changed in the new table, so all the suggestions to match times are AFAICT not gonna work. I think you're on the right track with ismember, assuming the combination of values in those vars are unique in each row. Dunno if that's true or not. But I think you need the 2nd output.
For each row in the old, you want to know where it ended up in the new. So you want the second output of
[tf,loc] = ismember(old,new)
then something like old.time will map to new.time(loc).
By the way, there is a table ismember method, something like
[tf,loc] = ismember(old(:,["Var1" "Var2"]),new(:,["Var1" "Var2"]))

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