If B is a matrix,what is the difference between B(1:end) and B(:)

If B=[1 2 ; 3 4]

B(1:end) returns [1 3 2 4] as a row vector and B(:) returns it as a column vector.

What is the difference?

Answer 1

[Stephen23]

Given a matrix B:

• B(1:end) uses linear indexing. The size of the output is the same as the size of the index (which in your example is a 1xN vector).
• B(:) is a special syntax that always returns a column vector.

Loren Shure's blog explained the first syntax as "C = A(B) produces output the size of B unless both A and B are vectors... When both A and B are vectors, the number of elements in C is the number of elements in B and with orientation of A."

source: https://blogs.mathworks.com/loren/2006/08/09/essence-of-indexing/

See also:

https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html

https://www.mathworks.com/help/matlab/math/array-indexing.html