multiple switch-case, get position value
显示 更早的评论
switch var
case {'ABC' 'ADE' 'AFG' 'AHI'}
Str = 'A';
case {'BAC' 'BDE' 'BFG' 'BHI'}
Str = 'B';
end
The above is my switch-case condition. Is there a way if i select
"ADE" The Str should be "A", and the pos should 2.
"BHI" The Str should be "B", and the pos should 4.
Is there a way i can do to get the position, or should i write switch-case again
采纳的回答
Guillaume
2017-10-3
switch ... case (or if ... elseif ...) statements are simple to understand and are great for beginners, but are very limited. To do what you want with a switch you'd have to split each of your case statement into 4, so you'd have
switch var
case 'ABC'
Str = 'A'; pos = 1;
case 'ADE'
Str = 'A'; pos = 2;
...etc
A much simpler way to do what you want is not to use switch at all, and just use look-up tables:
lookuptable = {{'ABC' 'ADE' 'AFG' 'AHI'}, 'A';
{'BAC' 'BDE' 'BFG' 'BHI'}, 'B'};
for row = 1:size(lookuptable, 1)
[found, pos] = ismember(var, lookuptable{row, 1});
if found
Str = lookuptable{row, 2};
break;
end
end
if found
fprintf('"%s" found, Str is "%s" and pos is %d\n', var, Str, pos);
else
fprintf('"%s" not found\n', var);
end
1 个评论
Walter Roberson
2017-10-3
[tf, idx] = ismember(Str, lookuptable(:,2));
if tf
var = lookuptable{idx,1}{pos};
else
var = '';
end
更多回答（2 个）
Walter Roberson
2017-10-3
Provided that you can sort the cases by initial letter and all the entries with the same initial letter are to be considered together,
cases = {'ABC' 'ADE' 'AFG' 'AHI', 'BAC' 'BDE' 'BFG' 'BHI'};
[vars, startpos, uidx] = unique( cellfun( @(V) V(1), cases ), 'stable');
Then,
[tf, idx] = ismember(var, cases);
if tf
groupidx = uidx(idx);
Str = vars(groupidx);
pos = idx - startpos(groupidx) + 1;
else
Str = ''; pos = [];
end
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