adding element to the beginning of an array

2020 7 21
1 个回答
回答已采纳
更新时间：2020 7 22
14 次查看（30 天）

0 个投票

I have a array which has been initialized with zeros, I would like to add four elements each time at the beginning of it while keeping its size the same,
I want to add the first four elements from a array to the first four elements to a second array(initialized with zeros) and then the next four till we have all the elements from the first one transfer to the second with the order that I have mentioned perviously and with the same manner.
I think it can be done without using loops, I would like to see the best way that Matlab offers to do this.
for example I have:
a = randi(10,1000,1);
% I want to add the first for elements from a to the beginning of b while keeping the size of b the same, and then the next four from a
% to be and so on..
b = zeros(2048,1);
Any help would be really appreciated :)

请先登录，再回答此问题。

 采纳的回答

madhan ravi
madhan ravi 2020-7-21

2 个投票

b(1:numel(a)) = a

7 个评论
显示 5更早的评论 隐藏 5更早的评论

Ali Abdulkarim
Ali Abdulkarim 2020-7-22
Thank you for answering, but how about doing it on stages, I mean at first 4 elements, then another four after them, till they reach 1000 ?
I mean
a = [1,2,3,4,5,6,7,8,9,10,11,12,13]
b = [0,0,0,0,0,0,0,0,0,0]
%%% first stage:
b = [1,2,3,4,0,0,0,0]
%%% second stage:
b = [1,2,3,4,5,6,7,8,0,0]
Ali Abdulkarim
Ali Abdulkarim 2020-7-22
Haha no, actually I am trying to self-learn a certain technology in telecommunications, and I need to have it as stages, becuase that's what real world transmission actually work, you send symbols, and each symbol carry a certain number of bits
madhan ravi
madhan ravi 2020-7-22
w = 1:8;
x = 1:4:numel(w);
y = 4:4:numel(w);
for k = 1:numel(w)/4
w(x(k) : y(k))
end
Ali Abdulkarim
Ali Abdulkarim 2020-7-22
Thanks, that is what I am looking for, is there a way in matlab to do it using inner loops, instead of for loop?
the output as ans is correct, how about appending the result to the zero initialized vedctor, instead of printing it, shall I use concatenation (cat) ?
madhan ravi
madhan ravi 2020-7-22
I answered your original question.
Ali Abdulkarim
Ali Abdulkarim 2020-7-22
In my original question, I have mentioned this, In other words I am not trying to extend the question, I have already accepted your answer, becuase It was helpful, thanks anyways

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Logical 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by