如何在文本集中创建所有字符组合？

发布于 2024-11-01 01:36:14 字数 347 浏览 4 评论 0原文

例如，我有这样的文本集：

Column 1:

a
b

Column 2:

l
m
n

Column 3 :

v
w
x
y

我想将它们组合起来以获得如下输出：

alv
alw
alx
aly
amv
amw
amx
amy
...

这将输出 24 种文本组合。如果我只使用前两列，它将输出 2*3=6 个组合。

我不知道如何在 MATLAB 中执行此操作。有什么建议吗？

原文

For example, I have sets of text like so:

Column 1:

a
b

Column 2:

l
m
n

Column 3 :

v
w
x
y

And I want to combine them to get an output like this:

alv
alw
alx
aly
amv
amw
amx
amy
...

Which will output 24 combinations of text. If I were to only use the first two columns, it will output 2*3=6 combinations.

I'm not able to figure out how to do this in MATLAB. Any suggestions?

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若无相欠,怎会相见 2024-11-08 01:36:14

一种解决方案是使用函数 NDGRID 生成所有组合集合中的索引数：

C = {'ab' 'lmn' 'vwxy'};            %# Cell array of text sets
sizeVec = cellfun('prodofsize',C);  %# Vector of set sizes
[index3,index2,index1] = ndgrid(1:sizeVec(3),...  %# Create all the index
                                1:sizeVec(2),...  %#   combinations for
                                1:sizeVec(1));    %#   the sets
combMat = [C{1}(index1(:)); ...  %# Index each corresponding cell of C and
           C{2}(index2(:)); ...  %#   concatenate the results into one matrix
           C{3}(index3(:))].';

对于 combMat，您应该得到以下结果：

alv
alw
alx
aly
amv
amw
amx
amy
anv
anw
anx
any
blv
blw
blx
bly
bmv
bmw
bmx
bmy
bnv
bnw
bnx
bny

如果您只想获得第 1 列和第 2 列的组合，请从对 NDGRID 并删除 C{3}(index3(:)) 来自 combMat 的计算。

如果您希望 C 成为字符串元胞数组的元胞数组，而不是字符数组的元胞数组，您仍然可以使用上面完全相同的代码。唯一的区别是combMat 最终将成为字符串元胞数组而不是字符数组。

更新：

我实际上创建了一个通用解决方案，可以计算任意数量的集合（字符数组或字符串元胞数组）的组合。您可以在此答案中找到密切相关的问题。要重现上面的示例，您可以像这样调用它：

combMat = allcombs(C{:});

One solution is to use the function NDGRID to generate all of the combinations of indices into your sets:

C = {'ab' 'lmn' 'vwxy'};            %# Cell array of text sets
sizeVec = cellfun('prodofsize',C);  %# Vector of set sizes
[index3,index2,index1] = ndgrid(1:sizeVec(3),...  %# Create all the index
                                1:sizeVec(2),...  %#   combinations for
                                1:sizeVec(1));    %#   the sets
combMat = [C{1}(index1(:)); ...  %# Index each corresponding cell of C and
           C{2}(index2(:)); ...  %#   concatenate the results into one matrix
           C{3}(index3(:))].';

And you should get the following for combMat:

alv
alw
alx
aly
amv
amw
amx
amy
anv
anw
anx
any
blv
blw
blx
bly
bmv
bmw
bmx
bmy
bnv
bnw
bnx
bny

If you just want to get combinations for columns 1 and 2, remove the first input and output arguments from the call to NDGRID and remove C{3}(index3(:)) from the computation of combMat.

If you instead want C to be a cell array of cell arrays of strings instead of a cell array of character arrays, you can still use the exact same code above. The only difference will be that combMat will end up being a cell array of strings instead of a character array.

UPDATE:

I've actually created a generalized solution that can compute combinations for any number of sets (either character arrays or cell arrays of strings). You can find it in this answer to a closely-related question. To reproduce the above example, you would call it like so: