Appending mixed types to strings seems a bit tricky. Is this the intended behaviour?

I understand why I get different results, but is seems wrong. Is this intended?

'1' + "1" + 1

ans = "111"

'1' + 1 + "1"

ans = "501"

Answer 1

[Rik]

It helps to do this step by step, which show that (while unintuitive), this is intended behavior.

Matlab evaluates code from left to right:

'1' + "1"

ans = "11"

ans + 1

ans = "111"

And your second example:

'1' + 1

ans = 50

ans + "1"

ans = "501"

Because the first call to plus doesn't know you want to use a string as an operand later, this results in a conversion to double, and since the UTF-16 encoding of '1' is uint16(49), this results in double(50).

You can avoid this by putting in some parentheses:

'1' + ( 1 + "1" )

ans = "111"

[Stephen23]

+1 nice, clear explanation.

[Tomazz]

Yes, I already understood why the results are the way they are, and thank you for very clear explanation. But before running into the issue, I never considered that code is strictly evaluated left to right. It seemed more intuitive to me that when appending strings with "+" operator, all terms were converted to strings before concatenation.

[Rik]

If you want to forget about this behavior, just make sure to always start with a string, even if it is empty:

"" + '1' + 1 + "1"

ans = "111"

[Tomazz]

Very nice solution, thanks.

[Stephen23]

"I never considered that code is strictly evaluated left to right."

This is explained in the MATLAB documentation: "Within each precedence level, operators have equal precedence and are evaluated from left to right". Plusses all have the same precedence.

Source: https://www.mathworks.com/help/matlab/matlab_prog/operator-precedence.html

[Tomazz]

Sure, it makes sense.

Still, I was a bit surprised that (S1+S2)+S3 is not equal to S1+(S2+S3) in this case.