Why does implicit conversion happen from 'char' to 'string' when concatenating?

Concatenating char arrays results in a new char array, as expected:

>> ['a', 'b', 'c']


ans =


'abc'

However, if any element of this array is a string, there is an implicit conversion of all the char arrays to strings, and the behavior is quite different:

>> ['a', "b", 'c']


ans =


1×3 string array


"a" "b" "c"

What is the reason for this?

Answer 1

[MathWorks Support Team]

In concatenation operations, the dominant object determines the class of the resulting array, according to the following documentation:

 

https://www.mathworks.com/help/matlab/matlab_oop/implicit-class-conversion.html#bvo4poc

Therefore, when the array contains both 'char' and 'string', the concatenation results in a 'string' array.

The following documentation includes other related examples to demonstrate this idea:

 

https://www.mathworks.com/help/matlab/matlab_prog/concatenation-examples.html