Parse a cell array of strings without looping
4 次查看(过去 30 天)
显示 更早的评论
I've got a nx1 cell array of strings that correspond to spatial coordinates. Here's an example where n=4,
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
Each row of the cell array is a string containing x,y, and z coordinates separated by a comma. I need to parse each string to separate the coordinates, convert the coordinates to numbers, do an operation on them, then put them back in their original format. Is there a way to do this without looping through each row of the cell array? Any tips or insight would be greatly appreciated.
Regards, Justin
6 个评论
per isakson
2012-10-11
编辑:per isakson
2012-10-11
With 'Headerlines' and 'N' of textscan it would still be possible to read and parse in one step. However, you need to find out the values of the two first.
采纳的回答
Azzi Abdelmalek
2012-10-11
编辑:Azzi Abdelmalek
2012-10-11
clear
A={'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'}
B=cellfun(@(x) regexp(x,',','split'),A,'uni',false)
out=cell2mat(cellfun(@(x) [cellfun(@(y) str2num(y),x)],B,'uni',false))
%or easier
out=str2num(cell2mat(A))
更多回答(2 个)
Matt Fig
2012-10-11
编辑:Matt Fig
2012-10-11
C = {'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'};
% Extract the numbers:
D = cellfun(@str2num,C,'Un',0);
% Do the 'operation' on the coords with cellfun:
E = cellfun(@(x) x+[1 2 3],D,'Un',0)
% Put them back in original format.
F = cellfun(@(x) sprintf('%.4f,',x),E,'Un',0)
Note that the step from D to E is ambiguous given your description, but you get the idea.
0 个评论
per isakson
2012-10-11
编辑:per isakson
2012-10-11
On possibility for your first step - if the file is not huge:
str = {
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
'122.8233,216.1323,671.8740'
};
M = str2num( char(str) );
or I didn't get it.
3 个评论
per isakson
2012-10-11
编辑:per isakson
2017-2-9
cellstr( num2str( M, '%f,%f,%f\n' ) )
However, write the numerical array directly to the file with fprintf in a loop I guess that fast enough. Otherwise, transpose the numerical array and write with fprintf, but only if profile showed that it could be worth the trouble.
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Data Type Conversion 的更多信息
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!