Using cellfun to pull information

Hopefully I can explain this!

I have the following code:

clear;
clc;
%--------------------------------------------------------------------------

% Table 1
Color1 = ["Blue"; "Orange";"Purple";"Blue";"Fuschia";"Red"];
LiscensePlate1 = [12569;12897;56783;45231;78999;99999];
t1first = datetime(2021,1,1,0,0,0);
t2first = datetime(2021,1,1,3,0,0);
tfirst = t1first:minutes(35):t2first;
tfirst=tfirst';
cars1 = table(Color1,LiscensePlate1,tfirst);

%--------------------------------------------------------------------------

%--------------------------------------------------------------------------

% Table 2
Color2 = ["Blue"; "Orange";"Purple";"Blue";"Fuschia";"Red"];
LiscensePlate2 = [88888;12897;77777;45231;88999;99999];
t1second = datetime(2022,1,1,2,0,0);
t2second = datetime(2022,1,1,5,0,0);
tsecond = t1second:minutes(35):t2second;
tsecond=tsecond';
cars2 = table(Color2,LiscensePlate2,tsecond);

%--------------------------------------------------------------------------

For this example, say I am out watching cars on my street corner on two different days and I write down the above information (color, liscense plate number, and the time I saw the car).

Is there any way to use cellfun to search between the two tables and see if any of the liscense plate numbers match? If they match, how would I then pull the time I saw the cars and see when the difference is between the time I first saw the car and the second?

I know with a table this small and I could look for the matching liscense plates easily but I am actually dealing with a larger data set and would need this automated (cellfun) if possible!

Thank you in advance for all of your help!

Answer 1

[Jan]

cellfun works on cell arrays, as the name says. You are working with tables. So this command does not match at all.

Color1 = ["Blue"; "Orange";"Purple";"Blue";"Fuschia";"Red"];
LiscensePlate1 = [12569;12897;56783;45231;78999;99999];
t1first = datetime(2021,1,1,0,0,0);
t2first = datetime(2021,1,1,3,0,0);
tfirst = t1first:minutes(35):t2first;
tfirst=tfirst';
cars1 = table(Color1,LiscensePlate1,tfirst)

cars1 = 6×3 table
     Color1      LiscensePlate1           tfirst       
    _________    ______________    ____________________

    "Blue"           12569         01-Jan-2021 00:00:00
    "Orange"         12897         01-Jan-2021 00:35:00
    "Purple"         56783         01-Jan-2021 01:10:00
    "Blue"           45231         01-Jan-2021 01:45:00
    "Fuschia"        78999         01-Jan-2021 02:20:00
    "Red"            99999         01-Jan-2021 02:55:00

% Table 2
Color2 = ["Blue"; "Orange";"Purple";"Blue";"Fuschia";"Red"];
LiscensePlate2 = [88888;12897;77777;45231;88999;99999];
t1second = datetime(2022,1,1,2,0,0);
t2second = datetime(2022,1,1,5,0,0);
tsecond = t1second:minutes(35):t2second;
tsecond=tsecond';
cars2 = table(Color2,LiscensePlate2,tsecond);

[match, index] = ismember(cars1.LiscensePlate1, cars2.LiscensePlate2)

match = 6×1 logical array
   0
   1
   0
   1
   0
   1

index = 6×1

0 2 0 4 0 6

cars1(match, :)

ans = 3×3 table
     Color1     LiscensePlate1           tfirst       
    ________    ______________    ____________________

    "Orange"        12897         01-Jan-2021 00:35:00
    "Blue"          45231         01-Jan-2021 01:45:00
    "Red"           99999         01-Jan-2021 02:55:00

cars2(index(match), :)

ans = 3×3 table
     Color2     LiscensePlate2          tsecond       
    ________    ______________    ____________________

    "Orange"        12897         01-Jan-2022 02:35:00
    "Blue"          45231         01-Jan-2022 03:45:00
    "Red"           99999         01-Jan-2022 04:55:00

By the way, the word is "license", not "liscense".