How to sort a table by two columns?

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Anja Lauer
Anja Lauer 2018-12-5
评论： Anja Lauer 2018-12-6
Hello,
I want to sort a table by two column. The table hast three columns in total, one of them is a string. It looks kindof like this:
T= [1 4 'a';
3 2 'b';
1 3 'c';
1 1 'd';
2 5 'e';
3 3 'f';
2 2 'g']
and I want it to look like this:
T_new= [ 1 1 'd';
1 3 'c';
1 4 'a';
2 2 'g';
2 5 'e':
3 2 'b';
3 3 'f']
I tried using the Function:
T=sortrows(T,[1 2]);
but it only sorts the first column but not the second:
T_false= [ 1 4 'a';
1 3 'c';
1 1 'd';
2 5 'e';
2 2 'g';
3 2 'b';
3 3 'f']
I think it's pry because of the third column being a string because I have been using this function befor with only numeric matrices and it worked fine.
I would be thankful for any tipps.
Thank you, Anja

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Kevin Chng
Kevin Chng 2018-12-5
编辑：Kevin Chng 2018-12-5
I follow your solution, it sorts two columns for me.
See :
a = [1 3 1 1 2 3 2];
b = [4 2 3 1 5 3 2];
c = ['a' 'b' 'c' 'd' 'e' 'f' 'g'];
t=table(a',b',c');
t = sortrows(t,[1,2])
Result :
T =
7×3 table
Var1 Var2 Var3
____ ____ ____
1 1 d
1 3 c
1 4 a
2 2 g
2 5 e
3 2 b
3 3 f
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Kevin Chng
Kevin Chng 2018-12-5
Hi Anja,
Your updated one is correct, there are many unseen decimal point. try:
format long
load testtable.mat
H = sortrows(H,[1,2]);
%display the top 10, then you will understand
H(1:,10,:)
from the code above, you will understand since some decimal point is hidden.
Accept my answer if it answers your question.
Anja Lauer
Anja Lauer 2018-12-6
I did not think about the hidden decimal points! Thank you so much! I know what to do now!

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