"warning takes sprintf-like arguments directly" not entirely true?
9 次查看(过去 30 天)
显示 更早的评论
If I write this:
message = sprintf('%d %d %d', [1 2 3])
warning(message)
I get a warning from MATLAB Code Analyzer at the second line, saying "warning takes sprintf-like arguments directly".
However if I follow its recommendation and I type:
warning('%d %d %d', [1 2 3])
I get the error "Formatted arguments cannot be non-scalar numeric matrices.".
Is this the desired behaviour?
4 个评论
回答(2 个)
Image Analyst
2018-9-19
Get rid of the brackets so you have scalars instead of a vector:
>> warning('%d %d %d', [1 2 3])
Error using warning
Formatted arguments must be scalar.
>> warning('%d %d %d', 1, 2, 3)
Warning: 1 2 3
So it must not like that fact that you're trying to put in one matrix with 3 format specifiers (%d).
2 个评论
Jan
2018-9-19
编辑:Jan
2018-9-19
This is the documented behavior [EDITED] since R2018b:
doc warning
You find:
warning(msg,A1,...,An)
A1,...,An — Values
character vector | string scalar | numeric scalar
Values that replace the conversion specifiers in msg, specified as a
character vector, string scalar, or numeric scalar.
[1,2,3] is not a numeric scalar.
So either use sprintf or provide the elements separately:
data = [1,2,3];
dataC = num2cell(data);
warning('%d %d %d', dataC{:})
While it is documented, one could still discuss, if this is the "desired" behavior. I did not struggle with this feature in the last 20 years.
8 个评论
Matthias Roosz
2022-1-28
An old topic - but still annoying for those not switching to new matlab releases every year...
IMHO totally undesired behaviour. I liked using sprintf-like arguments to warning (and error) - as the message hint STILL suggests. All code relying on dealing array values to multiple format specifiers breaks with the change to R2018b or later with no hint to be found in the release notes or the code analyzer :'(
distrib = [0.23 3.1415 123.4]; % dummy values
% warning('bad distrib (1%%/median/99%%): %.1f/%.2f/%.1f', distrib) % used to work
warning('bad distrib (1%%/median/99%%): %.1f/%.2f/%.1f', distrib(1), distrib(2), distrib(3)) % how is this better?
distribC = num2cell(distrib);
warning('bad distrib (1%%/median/99%%): %.1f/%.2f/%.1f', distribC{:}) % or this?
A solution (apart from repeating the variable name holding the data to be printed) that does not require an extra line of code before each warning/error would still be interesting. Maybe we'll get something like python's *args? I've tried this
expand = @(x) x{:};
warning('bad distrib (1%%/median/99%%): %.1f/%.2f/%.1f', expand(num2cell(distrib)))
but no luck because the function only 'sees' one argout, thus only reports the first value...
Walter Roberson
2022-1-29
No mlint warning for this, at least not in current releases:
distrib = [0.23 3.1415 123.4]; % dummy values
SIT = @(x) struct('d', num2cell(x));
warning('bad distrib (1%%/median/99%%): %.1f/%.2f/%.1f', SIT(distrib).d)
This relies upon a somewhat new feature, that the return value of a function call may now be indexed with dot notation. Unfortunately I am having difficulty finding the appropriate release notes entry to say which release this started with.
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Logical 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!