dlmwrite/dlmread function help ?

I had a matrix

A = [data1 data2 data3];
B = [data4 data5];

data1,data2,....data5 are calculated or exported from excel files, these some data are randomly generated so I want to store data data2 and data4 in a matrix AA when I run it first and then run in 2nd time stored in BB. How to use dlmwrite without creating text file or creating with text file ?

[per isakson]

I edited the question to improve readability.

[Jan]

"How to use dlmwrite without creating text file or creating with text file": This is not clear. It is the purpose of dlmwrite to create a file, therefore it is impossible to use it without creating a file. What is the actual problem?

Answer 1

[per isakson]

• dlmwrite writes to a text file. That's the purpose and you cannot avoid it.
• "matrix AA [...] BB" see TUTORIAL: Why Variables Should Not Be Named Dynamically
• the results could be stored in a cell array, a structure array, a table or ... . There are many alternatives.

In response to comment

This small experiment illustrates how to store a matrix to a text file and restore the matrix from the text file. In this case, there will be a precision loss, however, you may specify the precision that dlmwrite shall use.

Create a matrix

>> A = rand( 3, 5 )
A =
    0.8147    0.9134    0.2785    0.9649    0.9572
    0.9058    0.6324    0.5469    0.1576    0.4854
    0.1270    0.0975    0.9575    0.9706    0.8003

store the matrix data to a text file

>> dlmwrite('file_with_data_of_A.txt', A )

inspect the content of the text file

>> type file_with_data_of_A.txt
0.81472,0.91338,0.2785,0.96489,0.95717
0.90579,0.63236,0.54688,0.15761,0.48538
0.12699,0.09754,0.95751,0.97059,0.80028

and finally, restore the matrix

>> B = dlmread('file_with_data_of_A.txt')
B =
    0.8147    0.9134    0.2785    0.9649    0.9572
    0.9058    0.6324    0.5469    0.1576    0.4854
    0.1270    0.0975    0.9575    0.9706    0.8003
>>

[MUKESH KUMAR]

then how can I store those data first in text file and then use of dlmwrite ?

[Jan]

No, you do not store them in a text file and use dlmwrite afterwards. dlmwrite is the command to write the text file.

[MUKESH KUMAR]

when I run program 2nd time then I want to use first run data , how is it possible then ? thanks for help

[per isakson]

We have a communication problem.

"how can I store those data first in text file" I would rather say that dlmwrite stores the data in a text file.

Try to explain what you want to do in other words.

[MUKESH KUMAR]

forget all, Lets say I have a randomly generated matrix A, now I want to store it in matrix B as text file or any suitable format and when I run program the second time then I will use the previous run data of B matrix in next equations ,each time ? Note that I dont want to save the A matrix as .mat file first.

[per isakson]

See the addendum of my answer. I might have missed your intention of introducing B