2

我有两个矩阵，如下所示：

'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：

'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

关于如何加入这些表的任何想法？干杯。

编辑：真的很抱歉我的错别字，伙计们。我更新了问题和输入/输出数据。请随时提供建议。

4

3 回答 3

9

我相信您要实现的目标在数据库世界中称为内部联接和完全外部联接。

首先我们从两个数据集开始：

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
};

下面是执行这两种类型的连接的代码：

%# 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：

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

无论哪种方式，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]
于 2012-06-12T15:09:39.160 回答
3

在 MATLAB 中，不能将字符串作为矩阵元素。为此，您需要使用元胞数组。这是使用元胞数组和containers.Maps 的解决方案。

FirstCellArray = {
'01/01/2010', 1;
'02/01/2010', 2;
'03/01/2010', 3;
'05/01/2010', 11;
'06/01/2010', 17
};

SecondCellArray = {
'01/01/2010', 4;
'02/01/2010', 5;
'04/01/2010', 6;
'05/01/2010', 7;
};

AllDatesCellArray = union(FirstCellArray(:,1), SecondCellArray(:,1));

% 为两个元胞数组创建containers.Maps。containers.Maps 是哈希表。

DateToFirstNumberMap = containers.Map(FirstCellArray(:,1), FirstCellArray(:,2));
DateToSecondNumberMap = containers.Map(SecondCellArray(:,1), SecondCellArray(:,2));

WithNaNsCellArray = AllDatesCellArray;

for Index = 1:size(WithNaNsCellArray, 1)
    Key = AllDatesCellArray{Index, 1};
    try
        NumberOne = cell2mat(values(DateToFirstNumberMap, cellstr(Key)));
    catch
        NumberOne = NaN;
    end
    WithNaNsCellArray{Index, 2} = NumberOne;
    try
        NumberTwo = cell2mat(values(DateToSecondNumberMap, cellstr(Key)));
    catch
        NumberTwo = NaN;
    end
    WithNaNsCellArray{Index, 3} = NumberTwo;
end

WithoutNaNsCellArray = WithNaNsCellArray;
NaNIndicesVector = (isnan([WithNaNsCellArray{:,2}]) | isnan([WithNaNsCellArray{:,3}]));
WithoutNaNsCellArray(NaNIndicesVector == 1, :) = [];

然后WithNaNsCellArray包含有NaN行的结果并WithoutNaNsCellArray包含没有NaN行的结果。

WithNaNsCellArray = 
'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]

WithoutNaNsCellArray = 
'01/01/2010'    [ 1]    [4]
'02/01/2010'    [ 2]    [5]
'05/01/2010'    [11]    [7]
于 2012-06-11T15:28:14.753 回答
0

统计工具箱包含一个名为 JOIN 的函数，它基本上可以满足您的需求。

http://www.mathworks.de/de/help/stats/dataset.join.html

不幸的是，它可能无法处理字符串和多类型矩阵。但是您也许可以使用 JOIN 来缩短其他答案提出的解决方案。

于 2013-02-28T15:13:23.343 回答