How to combine two tables with same variable name without change anything in the table

I have performed a lot of experiments and got over 50 xlsx files with over 10 arrays data in it, and each of them has the same variable names and datas, such as:

1. Experiment 1: made at 2018, the injection rate is 0.146ml/min

The content in the xlsx flie which was recored is:

        Slice                   Time      X        Y
2018-bz-10-0.146-001.png        0.1    123.10  155.84 
2018-bz-10-0.146-002.png        0.3    115.28  155.443
2018-bz-10-0.146-003.png        0.6    116.36  155.406 

2. Experiment 2: made at 2018, the injection rate is 2.128ml/min

The content in the xlsx flie which was recored is:

        Slice                   Time     X       Y
2018-bz-10-2.128-001.png        18.5   11.68   128.08
2018-bz-10-2.128-002.png        36.4   130.89  155.4

P.S. The second file just have two slices as the camera for the image slices stops earlier.

I use 'readtable' to import these xlsx files. As there are too much of them, I decide to combine all of the xlsx into one parallel table, and save it as one xlsx. Just like

        Slice                   Time     X       Y              Slice                   Time      X        Y
2018-bz-10-2.128-001.png        18.5   11.68   128.08     2018-bz-10-0.146-001.png      0.1    123.10  155.84 
2018-bz-10-2.128-002.png        36.4   130.89  155.4      2018-bz-10-0.146-002.png      0.3    115.28  155.443
2018-bz-10-2.128-003.png        45.4    NaN     NaN       

Therefore, depend on this single xlsx, I can efficiently organize my datasets and copy these data to other places, while any of the data in it could be traced to its original source. Furthermore, I could modify the .m to particularly extract two arrays in all xlsx into one xlsx for further comparisons.

So could any help me about this? It seems just a simple combination of data, but matlab told me

Cannot find a common table variable to use as a key variable.

Or:

Duplicate variable name: 'Slice'.

So any solutions? Thanks!

[Peter Perkins]

although you have not provided anything in the way of code, it appears that you tried to use join and horizontal concatenation. Not only that, but if you tried to join the two tables you showed, clearly there are common variables to use as keys. So you're gonna need to be a whole lot more specific about what you are doing.

It looks like you're trying to put the two tables side-by-side. That doesn't seem to make sense, since they have different numbers of rows. It seems like vertical concatenation should be what you want.

[Sandy Woo]

Hi Peter

Thank you very much for your reply! The situation is that I have performed over 50 sets of experiments, and record the parameters of each of them, which were stored in different xlsx files. Now I wish to combine them together into one xlsx file, e.g. the 1.xlsx and 2.xlsx into 3.xlsx. So how could I do that in matlab?

I try to combine the two tables side-by-side so that I could plot them as the format of 'xyxy'. In my experiments, I cannot ensure the measurement time for each set of experiments is equivalent. Some experiments just started earlier. So the xlsx files have different numbers of rows. I wrote the code like:

A = readtable('C:\Users\s\Desktop\1.xlsx');
B = readtable('C:\Users\s\Desktop\2.xlsx');
C = cat(2,A(:,2),A(:,3),B(:,2),B(:,3));

But matlab warns like:

Error using tabular/cat (line 14)
All tables in the bracketed expression must have the same number of rows.

So how could I achieve a matrix of table like 3.xlsx? Thanks a lot for this!

[Peter Perkins]

This question doesn't make sense to me. Here are your two tables:

>> A = readtable('1.xlsx')
A =
  3×4 table
               Slice                Time      X         Y   
    ____________________________    ____    ______    ______
    {'2018-bz-10-0.146-001.png'}    0.1      123.1    155.84
    {'2018-bz-10-0.146-002.png'}    0.3     115.28    155.44
    {'2018-bz-10-0.146-003.png'}    0.6     116.36    155.41
>> B = readtable('2.xlsx')
B =
  2×4 table
               Slice                Time      X         Y   
    ____________________________    ____    ______    ______
    {'2018-bz-10-2.128-001.png'}    18.5     11.68    128.08
    {'2018-bz-10-2.128-002.png'}    36.4    130.89     155.4

They have no values in common on which to join them, nor do they have the same number of rows. I don't see any way to sensibly put them side-by-side.

If you want something otyher than

>> [A; B]
ans =
  5×4 table
               Slice                Time      X         Y   
    ____________________________    ____    ______    ______
    {'2018-bz-10-0.146-001.png'}     0.1     123.1    155.84
    {'2018-bz-10-0.146-002.png'}     0.3    115.28    155.44
    {'2018-bz-10-0.146-003.png'}     0.6    116.36    155.41
    {'2018-bz-10-2.128-001.png'}    18.5     11.68    128.08
    {'2018-bz-10-2.128-002.png'}    36.4    130.89     155.4

you will need to explain much more clearly.