import same variable without overwrite
显示 更早的评论
I try to import one single point from 20 different mat file and save those point into a mat file without overwrite it. However my code keep overwritting it and only display the last value. Here is my code
for k = 1:20
myfilename = sprintf('Image%d.mat', k);
a = load(myfilename);
newimg = (a.img -273);
% The point of plants
i = 100;
j = 84;
% Take the average of itself and all four of its neighboring
% values average each point in array
newimg(i,j) = 0.2*(newimg(i+1,j) + newimg(i-1,j) + newimg(i,j+1) + newimg(i,j-1) + newimg(i,j))
val = newimg(i,j)
newa = length(k);
save('newa.mat','-append','val');
end
1 个评论
Stephen23
2016-5-1
Rather than save your variable to the .mat-file on each iteration, simply construct an array with those values, and then save the array once after the loop, something like this:
N = 20;
mat = NaN(1,N); % preallocate
for k = 1:N;
...
mat(k) = val;
end
save(..., 'mat')
采纳的回答
Azzi Abdelmalek
2016-5-1
编辑：Azzi Abdelmalek
2016-5-1
You are using the same variable name. If you want to append your new data, you have to store them in a new variable name. But its better if you create a cell array then each update of your data, the size of your cell array will increase
For example
for k=1:3
a{k}=randi(4,4);
save('file','a','-append')
end
3 个评论
Stephen23
2016-5-1
There is no need to use a cell array, a simple numeric array will work perfectly, and is simpler. Some preallcoation would be nice though!
Azzi Abdelmalek
2016-5-1
That depends on the size of the new data
Ki Lung Chan
2016-5-1
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
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
