Find cell array and replace with another cell array in main cell array?
显示 更早的评论
I have 3 cell arrays. A={true;true;true;false;false;true;true;true;false;true;true;true;false;false;false}; How can I find B={true,true,true}; in A
and how can I replace that founded part with C={K;L;M};??
2 个评论
Cam Salzberger
2017-11-3
Can I ask why you are using a cell array? Are K, L, and M all logical values as well?
If that's the case, generally a logical array would be more memory-efficient, parsing time-efficient, and allow for simpler code.
Ali Tunahan EROL
2017-11-4
采纳的回答
Not efficient -- see below...
% code
A = {true;true;true;false;false;true;true;true;false;true;true;true;false;false;false};%logical row vector
B = {true,true,true};%logical col vector
C = {false,false,false};% assumption: replacement must also be logical col vector
% Convert all to strings, use regexprep, convert back
Rchar = regexprep(num2str(cell2mat(A))',num2str(cell2mat(B)')',num2str(cell2mat(C)')');
% Have to use _arrayfun_ since the output type must also be a cell array
R = arrayfun(@(x) {logical(x)},str2num(char(split(Rchar,''))))';
based in Guillaume comment:
% code
A = {true;true;true;false;false;true;true;true;false;true;true;true;false;false;false};%logical row vector
B = {true,true,true};%logical col vector
C = {false,false,false};% assumption: replacement must also be logical col vector
R = logical(strrep(cell2mat(A'),cell2mat(B),cell2mat(C)))
%need to convert logical array to cell array ??
Based on Cam comment:
%code
Rchar2 = regexprep(char(cell2mat(A)+'0')',char(cell2mat(B)+'0'),char(cell2mat(C)+'0'));
R2 = arrayfun(@(x) {logical(x)},str2num(char(split(Rchar2,''))))';
3 个评论
Cam Salzberger
2017-11-3
Pretty close for the adaption of my idea. There's still no need for str2num though - just use the same trick to convert it back:
R2 = logical(Rchar2-'0');
And if you really want a cell array:
R2cell = num2cell(R2);
Cedric
2017-11-3
Careful, STRREP and REGEXPREP are not working the same way. Regexp engines "eat" the string, STRREP does not:
>> strrep( 'aaa', 'aa', 'bb' )
ans =
'bbbb'
>> regexprep( 'aaa', 'aa', 'bb' )
ans =
'bba'
and STRFIND operates like STRREP:
>> strfind( [true,true,true], [true,true] )
ans =
1 2
Ali Tunahan EROL
2017-11-4
更多回答（1 个）
Cam Salzberger
2017-11-3
Ali,
Regardless of your reason for using cell arrays initially, it is likely to be faster to convert them to logical arrays before searching for the pattern. Chenchal shows you how to do that with cell2mat.
However, I would not recommend converting the logical values into character representations of their values (i.e. converting true into '1' and false into '0'). The conversion from number to character and back takes significant time that is likely to be unnecessary.
Once you have your logical arrays, you can use any of the algorithms mentioned in this blog post to find the location of the patterns, and then replace them with simple indexing and assignment.
If you would like to use any string-search functionality, rather than using num2str, I'd recommend just converting the logical values directly to some character values. It doesn't really matter which character value it is, so long as you can do matching with it. For easy of examination though, you could just do this:
charArray = char(logicalArray+'0');
Hope this helps!
-Cam
3 个评论
Guillaume
2017-11-3
I have to agree with Cam. I don't see the need for a cell array in the example provided, so if the logical values are indeed stored in a cell array, I would convert that into a bog standard logical vector.
Following that, a simple strfind will locate your pattern (despite its name, strfind works fine with numerical or logical vectors).
If the K, L and M symbols do not stand for logical values, then I'd say that there is something fundamentally wrong in what you're doing. An heterogeneous container where most of the values are logical but a few are some other types really does not sound right. What is the use case?
Chenchal
2017-11-3
Hey thank you Guillaume, I did not realize that! So below should do:
% code
A = {true;true;true;false;false;true;true;true;false;true;true;true;false;false;false};%logical row vector
B = {true,true,true};%logical col vector
C = {false,false,false};% assumption: replacement must also be logical col vector
R = logical(strrep(cell2mat(A'),cell2mat(B),cell2mat(C)))
R is a logical array, how to convert to cell array?
R is a logical array, how to convert to cell array
how about num2cell( R)?
类别
在 帮助中心 和 File Exchange 中查找有关 Cell Arrays 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
