Taking the last value of a matrix or vector

2.050 visualizzazioni (ultimi 30 giorni)
Hi. How can I take a last term of a vector - since my vector dimensions change -, and plug it in somewhere else in my code without keep changing the code?
for example right now I do v(6) to get the 6th term. How can I do it for nth term.... Thanks

Risposta accettata

Walter Roberson
Walter Roberson il 9 Set 2011
v(end)
or
v(length(v))
  4 Commenti
Marcus
Marcus il 17 Feb 2019
In MATLAB R2015a, end is faster than length():
>> x = rand(1, 100);
>> tic; for i=1:1e6; y=x(end); clear('y'); end; toc
Elapsed time is 5.475081 seconds.
>> tic; for i=1:1e6; y=x(length(x)); clear('y'); end; toc
Elapsed time is 5.705095 seconds.
Sangbok Lee
Sangbok Lee il 17 Ott 2021
R2021a
I've tried it several times.
"end" is always slightly faster than "length()"
I think "end" works the same way using index numbers.
>> x=rand(10000);
>> tic; for i=1:1e7; y=x(end); clear y; end; toc
Elapsed time is 21.722168 seconds.
>> tic; for i=1:1e7; y=x(length(x),length(x)); clear y; end; toc
Elapsed time is 22.073104 seconds.
>> tic; for i=1:1e7; y=x(10000,10000); clear y; end; toc
Elapsed time is 21.818949 seconds.

Accedi per commentare.

Più risposte (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by