it says error using assert, assertion failed and error in iuntitled (line 10) assert(ischar(in))

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Ian
Ian 2022-6-16
编辑： Stephen23 2023-12-15
error using assert
Assertion failed
Error in iuntitled (line 10)
assert(ischar(in))
  3 个评论
显示 1更早的评论
Ian
Ian 2022-6-16
编辑：Geoff Hayes 2022-6-17
heres the code
function result = encodeCharacter(in)
% Encode a single character into the 16-bit sequence for the Code 39
% barcode format.
%
% Rupert Thomas, March 2016
%
% Thanks to (for the codes): % http://notionovus.com/blog/code-39-barcode-biscuits/#setup
assert(ischar(in));
assert(length(in)==1);
codesArray = {
'1010001110111010', '1110100010101110', '1011100010101110', '1110111000101010', ... % 0, 1, 2, 3
'1010001110101110', '1110100011101010', '1011100011101010', '1010001011101110', ... % 4, 5, 6, 7
'1110100010111010', '1011100010111010', '1110101000101110', '1011101000101110', ... % 8, 9, A, B
'1110111010001010', '1010111000101110', '1110101110001010', '1011101110001010', ... % C, D, E, F
'1010100011101110', '1110101000111010', '1011101000111010', '1010111000111010', ... % G, H, I, J
'1110101010001110', '1011101010001110', '1110111010100010', '1010111010001110', ... % K, L, M, N
'1110101110100010', '1011101110100010', '1010101110001110', '1110101011100010', ... % O, P, Q, R
'1011101011100010', '1010111011100010', '1110001010101110', '1000111010101110', ... % S, T, U, V
'1110001110101010', '1000101110101110', '1110001011101010', '1000111011101010', ... % W, X, Y, Z
'1000101011101110', '1110001010111010', '1000111010111010', '1000100010001010', ... % -, ., (space), $
'1000100010100010', '1000101000100010', '1010001000100010', '1000101110111010'}; ... % /, +, %, *
strCode39 = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%*';
idx = strfind(strCode39,upper(in)); % Force to upper case
if any(idx)
result = codesArray{idx};
else
error('Invalid input - character not part of the Code 39 set');
end
end

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回答（2 个）

Geoff Hayes
Geoff Hayes 2022-6-17
@Ian - as per the function comment, Encode a single character i. I suspect that you are passing something else i.e. a numeric value like
>> encodeCharacter(42)
Error using encodeCharacter (line 8)
Assertion failed.
Try doing
>> encodeCharacter('4')
ans =
'1010001110101110'
or any other character. Note that you can only pass in one character. If you pass in 2 or more, then a different assert will fire.
Cris LaPierre
Cris LaPierre 2022-6-17
Ran in:
That is what an assert does. If the assertion fails (here that means that in is not a char), then an error is thrown and the message 'Assertion failed.' is thrown.
% Assertion is true -> no error
in = '5';
assert(ischar(in))
% Assertion is false -> error
in = 5;
assert(ischar(in))
Error using assert
Assertion failed.
  2 个评论
Daniel Lyddy
Daniel Lyddy 2023-12-15
I hate the fact that it prints "Error using assert." That misleads developers into thinking they've coded up their assert() lines incorrectly.
I just want to print my own error message. The other stuff is confusing to my end users, and should only be printed as a default if I have not provided my own error message.
Stephen23
Stephen23 2023-12-15
编辑：Stephen23 2023-12-15
Ran in:
@Daniel Lyddy: it is also strangely inconsistent: ERROR does not state "Error using error":
error('some text')
some text
MATLAB versions until at least R2021a did not include the text "Error using assert", so it is a recent change:
Apparently someone meddled in something that worked perfectly. My guess is that new text was introduced with this behavior change in R2022a:
https://www.mathworks.com/help/matlab/release-notes.html?rntext=assert&startrelease=R2022a&endrelease=R2023b&groupby=release&sortby=descending&searchHighlight=assert
A related topic, where someone meddled with ERROR to try and "improve" it... thus rendering it useless:
https://www.mathworks.com/matlabcentral/answers/1814220-calling-the-error-function-does-not-print-the-line-number-in-r2022b

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