How to extract value from some row or column in a matrix

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Tran Hoa 2019-1-19

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https://ww2.mathworks.cn/matlabcentral/answers/440479-how-to-extract-value-from-some-row-or-column-in-a-matrix

评论： Afluo Raoual 2021-2-8

采纳的回答： madhan ravi

Dear members

I have two matrix

A is a matrix that has 100 row=[1 2 3 4 5 6 7 8 9 10 ......100]

B is a matrix that wants to get the value from row 1 to row 10, and from row 25 to row 35

How to get matrix B

Thank you

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Image Analyst 2019-1-19

Terminology note: your A is a special kind of matrix called a "row vector" since it is a horizontal list of 100 numbers. It has 100 columns, not 100 rows. It has only one row.

So not exactly sure what you have, but madhan gives several options to choose from below in his answer, depending on what you have.

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madhan ravi 2019-1-19

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https://ww2.mathworks.cn/matlabcentral/answers/440479-how-to-extract-value-from-some-row-or-column-in-a-matrix#answer_357087

编辑：madhan ravi 2019-1-19

在 MATLAB Online 中打开

By indexing like shown below:

% if A is a matrix
A=rand(100); % fake data
B=A([1:10 25:35],:) % extracts specified rows
B=A(:,[1:10 25:35]) % extracts specified columns
% if A is a vector then
A=1:100; % fake data (row vector) , (1:100).' - column vector
B=A([1:10 25:35]) % extracts specified elements (1D-a vector)