# What does mean .* and ' ?

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Oliver Lestrange on 16 Aug 2020
Answered: Steven Lord on 7 Sep 2020
Hi,
It seems that in MATLAB exists the notation .* that seems to be an operation and the notation ' that is used apparently with variables.
What is the meaning of these notations?

Steven Lord on 7 Sep 2020
The .* operator performs element-wise multiplication.
The ' character has at least three potential meanings that I can think of offhand.
The first potential meaning is that of the complex conjugate transpose.
A = [1 2+3i; 4 5+5i]
B = A'
Note that each row in B contains the same values as the corresponding column of A, except that complex numbers are replaced with their complex conjugates.
The second potential meaning is to create a char vector. This could be what Sara Boznik meant with "you use it usually when you want to have something displayed in Command Window."
x = 'apple'
The third is relevant inside a char vector. Two ' characters will create a single ' stored inside the char vector.
y = 'Simple, isn''t it?'

Sara Boznik on 16 Aug 2020
.* means matrix product, if you don't write . will Matlab product the numbers on the same position.
' you use it usually when you want to have something displayed in Command Window.
Good luck.
Stephen23 on 7 Sep 2020
Edited: Stephen23 on 7 Sep 2020
".* means matrix product, if you don't write . will Matlab product the numbers on the same position."
This is incorrect. In fact:
The difference is explained here:
"' you use it usually when you want to have something displayed in Command Window."
The complex conjugate transpose should be used when you need the complex conjugate transpose.

KSSV on 16 Aug 2020
Edited: KSSV on 16 Aug 2020
.* this mean element by element multiplication. https://www.mathworks.com/help/matlab/ref/times.html
Example:
A = [1 2 ; 3 4] ;
B = [5 6 ; 7 8] ;
C = A.*B
' this stands for transpose of a matrix. https://www.mathworks.com/help/matlab/ref/transpose.html
EXample:
A = [1 2 ; 3 4] ;
B = A'
##### 2 CommentsShowHide 1 older comment
Oliver Lestrange on 18 Aug 2020
Thanks a lot Stephen Cobeldick!

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