need help to reduce time for each loop

i have 2 tables taxidata.pickup and TaxiRegionsandZones.pickup, i want to compare those two col and if they match it should creat a new col in taxidata.pickupzones (as TaxiRegionsandZones is categorical ), the new taxidata.pickupzones should have the name to that category.

for k = 1 : length(taxidata.PickupZone)
% for Lower Manhattan
    for i = 1: length(TaxiRegionsandZones.LowerManhattan)
        if taxidata.PickupZone(k) == TaxiRegionsandZones.LowerManhattan(i)
            taxidata.PickupRegion(k) = "LowerManhattan";
        end
    end
    

i have tried this but it is taking a vary long time, is there any method to reduce the time

Answer 1

[KSSV]

You need not to run loop for this. Read about function ismemeber, ismembertol, knnsearch.

[lia,lob] = ismember(taxidata.PickupZone,TaxiRegionsandZones.LowerManhattan) ;

[the king]

so how should i add that to my table

[Rik]

Did you experiment with what ismember does? Did you read the documentation?

[the king]

yea, i am getting lob as index but just not getting how to add that to table.

i am new to matlab.

[Rik]

Can you see how lia and lob are related to the values of k and i for which you did the assignment?

If you have trouble with Matlab basics you may consider doing the Onramp tutorial (which is provided for free by Mathworks).