When execute the below code ? the error message appear 'Index exceeds the number of array elements'?

조회 수: 1 (최근 30일)
for i=1:16
M(end+1:end+4)=dec2bin(hex2dec(M_h(i)), 4);
Warning: Hexadecimal numbers representing integers greater than or equal to flintmax might not be represented exactly as double-precision floating-point values.
Index exceeds the number of array elements. Index must not exceed 1.

채택된 답변

Jérôme 2022년 9월 12일
M_h and M are string arrays because you used "". Here, you want to work with char arrays using '' (See for example these links for details about them: https://www.mathworks.com/help/matlab/characters-and-strings.html, https://www.mathworks.com/help/matlab/ref/char.html, https://www.mathworks.com/help/matlab/ref/string.html).
If you use the following code, you will not have the error anymore:
for i=1:16
M(end+1:end+4)=dec2bin(hex2dec(M_h(i)), 4);
  댓글 수: 3
Jérôme 2022년 9월 19일
In Text in String and Character Arrays, you can see that MATLAB shows how to access individual characters of a char array, but not for a string. Because strings are made to work at a higher level, not to work characters per characters, which is the perfect job for char arrays.
In your case, you can simply convert the string to a char array before your operation, and convert it back to a string after that:
M_h2 = convertStringsToChars(M_h);
for i=1:16
M2(end+1:end+4)=dec2bin(hex2dec(M_h2(i)), 4);
M = convertCharsToStrings(M2);
Otherwise, if you really want to manipulate string directly, I imagine it's possible using the function extractBetween.

댓글을 달려면 로그인하십시오.

추가 답변 (1개)

Walter Roberson
Walter Roberson 2022년 9월 21일
Using extractBetween() as suggested by @Jérôme is the approved way to work with characters inside strings. But you can also go to a lower level... which will give you faster code.
Double-quotes like you had is used for a string array, so below I show looping over a string array and using {} to extract characters
M = strings(size(M_h));
for K = 1 : numel(M_h)
this_M_in = M_h{K};
this_M_out = blanks(64);
for i=1:16
this_M_out(i*4-3:i*4)=dec2bin(hex2dec(this_M_in(i)), 4);
M(K) = string(this_M_out);
M = 2×1 string array
"1111111111111111111111111111111111111111111111111111111111111111" "1101111010101101101111101010111111011110101011011011111010101111"
  댓글 수: 2
Jérôme 2022년 9월 21일
Nice, I didn't know we could convert a string to a char array using {}.
Is this mentioned somewhere in the official MATLAB documentation?

댓글을 달려면 로그인하십시오.


Help CenterFile Exchange에서 Characters and Strings에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by