merging elements into a single cell array
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I have a 366x1 cell array named B. i would like to copy each row into another cell array like 2nd and 3rd value of 1st row will be merged with 2nd and 3rd value of 2nd row into a new cell array (as both index is 8). Similarly 2nd and 3rd value of 3rd row will be merged with 2nd and 3rd value of 4th row into a new cell of the same cell array (as both index is 17) and so on.
3 个评论
James Tursa
2017-11-6
Do all of the rows always have exactly three elements?
Satarupa Khamaru
2017-11-6
Image Analyst
2017-11-6
Can you save B to a .mat file and upload it so we can try to work with it?
回答（1 个）
James Tursa
2017-11-6
Does this do what you want?
C = cellfun(@(c)c(2:end),B,'uni',false);
v = cellfun(@(x)x(1),B);
u = unique(v);
result = arrayfun(@(x)[u(x),C{v==u(x)}],1:numel(u),'uni',false)';
5 个评论
Satarupa Khamaru
2017-11-6
James Tursa
2017-11-6
What about this?
M = cell2mat(B);
v = M(:,1);
u = unique(v);
result = arrayfun(@(x)M(v==u(x),2:end),1:numel(u),'uni',false);
Satarupa Khamaru
2017-11-6
James Tursa
2017-11-7
arrayfun( ) operates on each element of an array. In this case, it is the array formed by 1:numel(u). For each of these values 1, 2, 3, ..., numel(u), an output is generated by the first argument:
@(x)M(v==u(x),2:end)
This is a function handle, which picks off the rows of M that match u(x) and the 2nd through last columns of these rows. So in your example above, the 8 in the first column appears in the first two rows. So this function handle, when evaluated with a 1 input, generates this result:
M(v==u(1),2:end)
Since u(1) is 8, this is equivalent to:
M(v==8,2:end)
I.e., this picks off the rows of M where the first column contains an 8. The 2:end picks off all of the columns except the first column.
For the next element of the result, a value of 2 is used as input to the function handle, so you get this:
M(v==u(2),2:end)
which gives this
M(v==17,2:end)
Etc.
Finally, the ...,'uni',false,... stuff is simply to tell arrayfun( ) to put the results into a cell array.
Satarupa Khamaru
2017-11-7
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