How do we treat default output formats such as "ans = ...." etc.?

Question

In MATLAB and Octave, the default output looks like this (I guess this is relevant for other languages as well):

'This is a string'

ans =

This is a string

x = 'This is a string'

x =

This is a string

Using disp will give:

disp('This is a string')
This is a string

There are, as far as I can tell, (at least) three types of challenges where this is relevant:

1. The output should look exactly like this (maybe newlines and trailing spaces are OK)
   • This one is bankers: ans = ... is not OK
2. Remove elements, remove letters, etc. from an input string.
   • I believe ans = ... should be OK, since the output format is not specified.
3. "Output: A is greater than B if A > B", copy from STDIN to STDOUT
   • ?

What do we do when the question simply states:

• "Output a string"
• "Print to STDOUT"

This is quite important, since disp('String') is much longer than just String. Also, for those cases where ans = ... is OK, will x = ... also be OK?

---

Update:

There are some cases that have come up recently:

1. The following function returns no arguments, but will write x = 1 2 3 4 5 in the command window:

   function f;x=1:5
   

   I'm assuming this is disallowed?

2. The following is not a function, but also doesn't use disp. It results in the integers 1-10 being printed like i = 1, i = 2 etc. clearing the screen between each new number.

   for i=1:10,pause(1);clc;i,end
   

   I'm assuming this is disallowed?

Answer 1

"Output a string" typically implies that it can be returned from a function, in which case extraneous output like ans = and x = is irrelevant. But in any situation in which a full program is used, be it required or by choice, or a function that prints to STDOUT rather than returning the value is used, disp is required.

Answer 2

This depends on how strict the output requirements of the challenge are.

• Some challenges have very relaxed requirements on the output format. E.g. some just specify "any convenient, unambiguous format". In those cases, including ans = or x = in the output is fair game as it does in no way obscure the actual output and is quite a natural output for Matlab as well.
• Other challenges require a very exact output format, e.g. a specific string (think "Hello, World!"). Those will usually state that the output must contain nothing except what is specified. In this case ans = and x = are not fine unless they happen to match exactly the required output format.
• Some challenges will require such an exact output format, but make an exception for any fixed interpreter output which cannot possibly be suppressed. This exception would not include Matlab, as ans = and x = can be suppressed using ; and printing with disp or similar instead.