Matlab中的逻辑索引 [英] logical indexing in matlab

问题描述

请考虑以下示例:

time = [733774,733774,733775,733775,733775,733776,733776];
depth = [0,10,0,5,10,0,10];
d = [1,1.3,1,2.5,2.5,1,1.2];
data = horzcat(time',depth',d');

dz = 1;

在这里，我分别进行了三天的多次测量.第一天在2个不同的深度进行2次测量，第二天在3个深度进行3次测量，第三天在2个深度进行2次测量.

Here I have a number of measurements taken for three separate days. The first day has 2 measurements taken at 2 separate depths, the second day has 3 measurements taken at 3 depths and the third has 2 measurements taken at 2 depths.

我想生成一个新变量'newData'，它对数据中的值进行线性插值(interp1).但是，我只想在任何给定日期的测量次数超过2的情况下执行此操作.因此，对于上面的示例，这仅适用于733775.在这里，我想进行深度测量并增加垂直分辨率，例如

I would like to generate a new variable 'newData' which linearly interpolated (interp1) the values in data. However, I would only like to do this if the number of measurements for any given day exceeds 2. So, for the example above this would only apply to 733775. Here I would like to take the depth measurements and increase the vertical resolution e.g.

newDepth = min(depth):dz:max(depth);

但是只能在测量次数超过2的日子中执行此操作.因此，我所描述的结果应该是:

But only perform this for the days when the number of measurements exceed 2. The outcome of what I have described should therefore be:

733774  0
733774  10
733775  0
733775  1
733775  2
733775  3
733775  4
733775  5
733775  6
733775  7
733775  8
733775  9
733775  10
733776  0
733776  10

加上'data(:，3)'中的插值.

plus the interpolated values from 'data(:,3)'.

实现此目标的最佳方法是什么?

What would be the best way of achieving this?

推荐答案

这是执行此操作的一种方法(这次解决了OP的编辑版本):

Here's one way to do this (solving the edited version of the OP this time):

[idx,~,uniqueTimes] = grp2idx(time);

counts = hist(time,uniqueTimes);


%# expand data with counts greater than minCount
minCount = 2;
dz = 1;

expandedData = mat2cell(data,counts,3)

for ii = find(counts>minCount)'
    minZ = expandedData{ii}(1,2);
    maxZ = expandedData{ii}(end,2);

    intData(:,2) = (minZ:dz:maxZ)';
    intData(:,1) = expandedData{ii}(1,1);
    intData(:,3) = interp1(expandedData{ii}(:,2),expandedData{ii}(:,3),intData(:,2));

    expandedData{ii} = intData;

end

out = cat(1,expandedData{:})

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