# Return the number of rows of an array

6 views (last 30 days)
Riley on 25 May 2021
Commented: Riley on 25 May 2021
Hi, I just started using Matlab and is confused on how to extract the row indices/ row numbers.
For example, I have a function A:
A = [10 20 30 40 50 60 70 80 90 100]
I wanted to extract the row which has elements less than 50 so it will give
B= [1 2 3 4] (from row 1 to 4)
May I know how to do this? Any help and advice is greatly appreciated
Stephen23 on 25 May 2021
You seem to have confused rows with columns:
Your example A has only one row and ten columns, whereas your example B has one row and five columns.

Stephan on 25 May 2021
A = [10 20 30 40 50 60 70 80 90 100]
A = 1×10
10 20 30 40 50 60 70 80 90 100
B = A(A<50)
B = 1×4
10 20 30 40
##### 3 CommentsShow 1 older commentHide 1 older comment
Stephan on 25 May 2021
A = [10 20 30 40 50 60 70 80 90 100]
A = 1×10
10 20 30 40 50 60 70 80 90 100
[row, col] = find(A<50)
row = 1×4
1 1 1 1
col = 1×4
1 2 3 4
Riley on 25 May 2021
Thanks, Stephen!

Alex Alex on 25 May 2021
B=find(A<50)
Stephen23 on 25 May 2021
Note that strictly this returns the linear indices, not row (or column) subscript indices.
Riley on 25 May 2021
Thanks, Alex