在 MATLAB 中连接矩阵

问题描述

我有两个矩阵，如下所示:

I have two matrices like the following ones:

'01/01/2010'          1
'02/01/2010'          2
'03/01/2010'          3
'05/01/2010'         11
'06/01/2010'         17

'01/01/2010'          4
'02/01/2010'          5
'04/01/2010'          6
'05/01/2010'          7

，在 MATLAB 中做了一些棘手的事情后，我想创建以下三个矩阵:

, and after doing a few tricky things in MATLAB, I want to create the following three matrices:

'01/01/2010'          1          4
'02/01/2010'          2          5
'03/01/2010'          3        NaN
'04/01/2010'        NaN          6
'05/01/2010'         11          7
'06/01/2010'         17        NaN


'01/01/2010'          1          4
'02/01/2010'          2          5
'05/01/2010'         11          7

知道如何加入这些表吗?干杯.

Any idea on how to join these tables?Cheers.

对于我的错别字真的很抱歉，伙计们.我更新了问题和输入/输出数据.请随时提供建议.

Really sorry for my typos, guys. I updated both the question and the input/output data. Please, feel free to provide suggestions.

推荐答案

我相信您要实现的目标在数据库世界.

I believe what you are trying to achieve are called inner join, and full outer join in the database world.

首先我们从两个数据集开始:

First we start with the two datasets:

d1 = {
 '01/01/2010'          1
 '02/01/2010'          2
 '03/01/2010'          3
 '05/01/2010'         11
 '06/01/2010'         17
};
d2 = {
 '01/01/2010'          4
 '02/01/2010'          5
 '04/01/2010'          6
 '05/01/2010'          7
};

以下是执行两种连接的代码:

Here is the code to perform the two types of join:

%# get all possible dates, and convert them to indices starting at 1
[keys,~,ind] = unique( [d1(:,1);d2(:,1)] );

%# full outer join
ind1 = ind(1:size(d1,1));
ind2 = ind(size(d1,1)+1:end);

fullOuterJoin = cell(numel(keys),3);
fullOuterJoin(:) = {NaN};           %# fill with NaNs
fullOuterJoin(:,1) = keys;          %# union of dates
fullOuterJoin(ind1,2) = d1(:,2);    %# insert 1st dataset values
fullOuterJoin(ind2,3) = d2(:,2);    %# insert 2nd dataset values

%# inner join
loc1 = ismember(ind1, ind2);
loc2 = ismember(ind2, ind1);

innerJoin = cell(sum(loc1),3);
innerJoin(:,1) = d1(loc1,1);        %# intersection of dates
innerJoin(:,2) = d1(loc1,2);        %# insert 1st dataset values
innerJoin(:,3) = d2(loc2,2);        %# insert 2nd dataset values

或者，我们可以通过简单地删除具有任何 NaN 值的行来从外连接数据集中提取内连接:

Alternatively, we could have extracted the inner join from the outer join dataset by simply removing rows with any NaN values:

idx = all(~isnan(cell2mat(fullOuterJoin(:,2:end))), 2);
innerJoin = fullOuterJoin(idx,:);

无论如何，结果:

>> fullOuterJoin
fullOuterJoin =
    '01/01/2010'    [  1]    [  4]
    '02/01/2010'    [  2]    [  5]
    '03/01/2010'    [  3]    [NaN]
    '04/01/2010'    [NaN]    [  6]
    '05/01/2010'    [ 11]    [  7]
    '06/01/2010'    [ 17]    [NaN]

>> innerJoin
innerJoin =
    '01/01/2010'    [ 1]    [4]
    '02/01/2010'    [ 2]    [5]
    '05/01/2010'    [11]    [7]

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