Automatically identify two numbers within an matrix

Question

Alberto Acri 2023-2-16

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编辑： Antonios Dougalis 2023-2-16

采纳的回答： Voss

Is there any way to automatically locate two numbers within a matrix?

For example:

for the file "matrix_1.txt" I am interested in identifying the following numbers 194 (min) and 201 (max)
for the file "matrix.txt" I am interested in identifying the following numbers 175 (min) and 199 (max)

So I am interested in a code that can identify these numbers without me knowing them. Like the max/min command that identifies the max/min within a matrix for example.

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Alberto Acri 2023-2-16

Definitely ignore numbers smaller than 70.

John D'Errico 2023-2-16

You are not telling us enough information. You want to find a number, like the max and min, But they may not be the smallest or largest numbers in the matrix. In fact, they are not even close to that.

So apparently you know what you want, but cannot describe it. And the matrices you show are not at all clear in how you would decide on those specific values.

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Answer 1

Voss 2023-2-16

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编辑：Voss 2023-2-16

在 MATLAB Online 中打开

matrix = readmatrix('matrix.txt');
matrix_1 = readmatrix('matrix_1.txt');
min_matrix = min(matrix(matrix >= 70))
min_matrix = 174
max_matrix = max(matrix(matrix >= 70))
max_matrix = 199
min_matrix_1 = min(matrix_1(matrix_1 >= 70))
min_matrix_1 = 194
max_matrix_1 = max(matrix_1(matrix_1 >= 70))
max_matrix_1 = 201

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Answer 2

Mathieu NOE 2023-2-16

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编辑：Mathieu NOE 2023-2-16

在 MATLAB Online 中打开

hello Alberto

welcome back !

here a demo for the 'matrix.txt' case

the other one is basically the same , simply change the min / max values

 M = readmatrix('matrix.txt');
 
 value_min = 175;
 value_max = 199;
 
ind = find(M>=value_min & M<=value_max); % linear index 
 M(ind)  % show the M values (to double check)
 [r,c] = ind2sub(size(M),ind) % show corresponding row / col indexes