Get the specific digit of a number

Hello all,

I'm working on an exercise that has multiple parts. At one point of the code, I have to extract all the numbers of a matrix that ends with 3 or 7.

clear all;close all;clc;
load Q4.txt; %Q4 being a matrix of nxm elements with multiple numbers in it.
matrice_Q4 = Q4;
position37 = find(mod(matrice_Q4,10)== 3|7) 
val37 = matrice_Q4(position37)

%Tells me what are the numbers in question

What I want is to have the position of all the numbers in the matrix that ends with either 3 or 7.

Thank you very much.

Answer 1

[Walter Roberson]

MATLAB does not allow you to use "==" to compare to two different values at once. Something of the form A==B|C where you want to compare to B or C, can be rewritten as A==B|A==C

Answer 2

[dpb]

Wrong syntax for the combined logical operation and you're looking for what's left over to get the last digit, not the modulo value...

position37 = find(rem(matrice_Q4,10)== 3 | rem(matrice_Q4,10)==7);

Then, to display the results you might find

doc sub2indx

useful or you could use 'logical addressing' to show the positions in a grid if the problem space is small enough for screen space.

ADDENDUM: Actually, either rem or mod works here for the purpose...

[Walter Roberson]

Yes, mod() and rem() differ in how they handle negative numbers.