How to make a new table from two different table with common value?

Hello. I have 4800960x1 table T1, 77449x1 table T2.

T1 and T2 is like

column 1 column 2

datetime value

I want to make a new table with 3 columns(common datetime of T1 and T2, value of T1, value of T2)

So far, I made 77209x1 datetime C which is the common datetime of T1 and T2.

I tried to make a new 77209x3 table which has 3 columns(datetime of C, values from T1, values from T2).

for example:

C

2010-01-01 01:00:00

2010-01-01 02:00:00

2010-01-01 03:00:00

2010-01-01 04:00:00

T1

2010-01-01 01:00:00 10

2010-01-01 02:00:00 11

2010-01-01 03:00:00 12

2010-01-01 04:00:00 13

2010-01-01 05:00:00 14

2010-01-01 06:00:00 15

2010-01-01 07:00:00 16

2010-01-01 08:00:00 17

T2

2010-01-01 01:00:00 0

2010-01-01 02:00:00 1

2010-01-01 03:00:00 2

2010-01-01 04:00:00 3

result:

2010-01-01 01:00:00 10 0

2010-01-01 02:00:00 11 1

2010-01-01 03:00:00 12 2

2010-01-01 04:00:00 13 3

I tried to use innerjoin, but it didn't work because C was not a table.

How can I get the results I want?

Answer 1

[KSSV]

Let T1 and T2 be your tables having two columnn each.

idx = ismember(T.(1),T.(2)) ; 
T1 = T1(idx,:) ;
T1.(3) = T2.(2) ; 

Answer 2

[Wan Ji]

result has the same row number as T1 or T2?

result = table(C,'variablenames',{'datetime'});
result.value1 = T1.value(1:(size(result,1)),1);
result.value2 = T2.value(1:(size(result,1)),1);

Answer 3

[Eric Sofen]

You should be able to use innerjoin on T1 and T2 - no need for C. The innerjoin function calculates the equivalent of C as an intermediate step. I think @KSSV's answer will run into trouble if there are times in T2 that aren't in T1, because it's assuming that T1(idx,:) is the same size as T2.

[KSSV]

ismember finds the common dates in T1 and T2. idx will be logical.

[Eric Sofen]

Consider a modified version of @jeon's original sample data.

T1

2010-01-01 01:00:00 10

2010-01-01 03:00:00 12

2010-01-01 05:00:00 14

2010-01-01 07:00:00 16

2010-01-01 09:00:00 17

T2

2010-01-01 01:00:00 0

2010-01-01 02:00:00 1

2010-01-01 03:00:00 2

2010-01-01 04:00:00 3

idx = ismember(T1.(1),T2.(1))
idx =
  5×1 logical array
   1
   1
   0
   0
   0
   
T1 = T1(idx,:); % table with 2 rows.
T2.(3) = T2.(2) % Error because T2.(2) has 4 rows.
To assign to or create a variable in a table, the number of rows must match the height of the table.