Interpreting varargin name-value pairs.
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Chad Greene
il 1 Mag 2014
Risposto: Kevin Schroeder
il 20 Lug 2021
I've been writing a lot of functions lately. I like allowing the user to declare options in my functions using name-value pairs, but I have not found a good clean method of interpreting varargin. Here are two methods I tend to use, but both feel a bit clunky:
% Method 1:
for k = 1:length(varargin)
if strcmpi(varargin{k},'fontname')
fontname = varargin{k+1};
varargin{k+1}=[];
varargin{k}=[];
end
end
% Method 2:
nk = 1:length(varargin);
for k = 1:length(varargin)
if strcmpi(varargin{k},'fontsize')
fontsize = varargin{k+1};
nk(k:k+1) = [];
end
end
varargin = varargin(nk);
Is there a better standard procedure for interpreting a list of varargin arguments?
Risposta accettata
Sean de Wolski
il 1 Mag 2014
8 Commenti
Cedric
il 2 Mag 2014
Modificato: Cedric
il 2 Mag 2014
Hi Chad, almost there, look at the KeepUnmatched and Unmatched properties of the parser. You might also be interested in functions fieldnames and struct2cell if you want to build a comma separated list for passing unmatched param/values further.
Più risposte (3)
Kevin Schroeder
il 20 Lug 2021
If it is of any value to others, I have always used a switch case nested in a for loop.
function myFunction(varargin)
for setting = 1:2:nargin
switch varargin{setting}
case 'SettingName1'
value = varargin{setting + 1}
[]; %do stuff with value
case 'SettingName2'
value = varargin{setting + 1}
[]; %do stuff with value
case 'SettingName3'
value = varargin{setting + 1}
[]; %do stuff with value
otherwise
[];
end
end
end
Functionally it should be similar to the nested if statements, but it looks much cleaner.
0 Commenti
Justin
il 1 Mag 2014
I'm always a fan of cellfun.
inputExist = find(cellfun(@(x) strcmpi(x, 'fontname') , varargin));
if inputExist
fontsize = varargin{inputExist+1};
end
I have used this or something similar before. You can wrap this in a for loop that goes through your expected inputs and instead of assigning them directly to fontsize you could assign it to a structure like:
inputs.(currentName) = varargin{inputExist+1};
Let me know if that makes sense.
1 Commento
Cedric
il 2 Mag 2014
Modificato: Cedric
il 2 Mag 2014
STRCMPI does work on cell arrays, so there is no need to use CELLFUN. Yet, it is likely not to be suited here, because Chad would have to test for all possible parameter names for both the function and the internal function. Using the parser and its Unmachted property is more flexible for this reason.
Alexander
il 17 Lug 2016
Dont use inputParser if you need to codegen - it is not supported in R2016a.
1 Commento
Sean de Wolski
il 19 Lug 2016
With codegen, you won't be using variable number of inputs since everything needs to be defined.
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