[英]Matlab removing unwanted numbers from array
I have got a matlab script from net which generates even numbers from an inital value. 我有一个来自net的matlab脚本,它从初始值生成偶数。 this is the code. 这是代码。
n = [1 2 3 4 5 6];
iseven = [];
for i = 1: length(n);
if rem(n(i),2) == 0
iseven(i) = i;
else iseven(i) = 0;
end
end
iseven
and its results is this 它的结果是这样的
iseven =
0 2 0 4 0 6
in the result i am getting both even numbers and zeros, is there any way i can remove the zeros and get a result like this 在结果我得到偶数和零,是否有任何方法我可以删除零并获得这样的结果
iseven =
2 4 6
You can obtain such vector without the loop you have: 您可以在没有循环的情况下获得此类向量:
n(rem(n, 2)==0)
ans =
2 4 6
However, if you already have a vector with zeros and non-zeroz, uou can easily remove the zero entries using find
: 但是,如果您已经有一个带零和非零的向量,则可以使用find
轻松删除零条目:
iseven = iseven(find(iseven));
find
is probably one of the most frequently used matlab functions. find
可能是最常用的matlab函数之一。 It returns the indices of non-zero entries in vectors and matrices: 它返回向量和矩阵中非零项的索引:
% indices of non-zeros in the vector
idx = find(iseven);
You can use it for obtaining row/column indices for matrices if you use two output arguments: 如果使用两个输出参数,则可以使用它来获取矩阵的行/列索引:
% row/column indices of non-zero matrix entries
[i,j] = find(eye(10));
The code you downloaded seems to be a long-winded way of computing the range 您下载的代码似乎是计算范围的冗长方式
2:2:length(n)
If you want to return only the even values in a vector called iseven
try this expression: 如果您只想在名为iseven
的向量中返回偶数值, iseven
尝试以下表达式:
iseven(rem(iseven,2)==0)
Finally, if you really want to remove 0
s from an array, try this: 最后,如果你真的想从数组中删除0
,请尝试这样做:
iseven = iseven(iseven~=0)
Add to the end of the vector whenever you find what you're looking for. 只要找到您要查找的内容,就可以添加到矢量的末尾。
n = [1 2 3 4 5 6];
iseven = []; % has length 0
for i = 1: length(n);
if rem(n(i),2) == 0
iseven = [iseven i]; % append to the vector
end
end
iseven
要从程序中删除所有零,我们可以使用以下命令,命令是 -
iseven(iseven==0)=[]
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