reshape a char array
조회 수: 23 (최근 30일)
이전 댓글 표시
Hi,
I have the following MWE and I don't understand what matlab is producing:
I start with a simple 21-length char array:
ex = 'caggtgcagctggtgcagtct'
that I would like to reshape into a 7-by-3 array. Of course, I could use a loop for this, but I thought that I could just reshape it. However, when I do
reshape(ex, [7,3])
ans =
7×3 char array
'cag'
'agc'
'gca'
'gtg'
'tgt'
'ggc'
'ctt'
This makes no sense to me. I was expecting
'cag'
'gtg'
'cag'
'ctg'
'gtg'
'cag'
'tct'
I also tried reshape(ex, 7,3) and reshape(ex(:), 7, 3) without any luck. What is matlab doing? TIA
댓글 수: 1
Guillaume
2020년 2월 26일
Matlab is column major. This means that when you reshape something into something else, the something else is filled column by column, not row by row. So, indeed as David shows, to get the output you want you reshape then transpose.
채택된 답변
David Hill
2020년 2월 26일
reshape(ex,[3,7])';
First number is row and second is column. Matrix is numbered down first.
댓글 수: 2
Guillaume
2020년 2월 26일
You'll find a number of languages (C-based mostly) are row majors and an equivalent number are column-major (Matlab, Fortran, and other math-focused languages) while a few can't make their mind up (eg. OpenGL).
So, it's only counterintuitive if you've never been exposed to the other side.
추가 답변 (0개)
참고 항목
카테고리
Help Center 및 File Exchange에서 Loops and Conditional Statements에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!