Function MATLAB中函数参数名/值对的处理
我有一个函数，它将可选参数作为名称/值对Function MATLAB中函数参数名/值对的处理,function,matlab,arguments,function-parameter,name-value,Function,Matlab,Arguments,Function Parameter,Name Value,我有一个函数，它将可选参数作为名称/值对 function example(varargin) % Lots of set up stuff vargs = varargin; nargs = length(vargs); names = vargs(1:2:nargs); values = vargs(2:2:nargs); validnames = {'foo', 'bar', 'baz'}; for name = names validatestring(name{:},
function example(varargin)
% Lots of set up stuff
vargs = varargin;
nargs = length(vargs);
names = vargs(1:2:nargs);
values = vargs(2:2:nargs);
validnames = {'foo', 'bar', 'baz'};
for name = names
validatestring(name{:}, validnames);
end
% Do something ...
foo = strmatch('foo', names);
disp(values(foo))
end
example('foo', 1:10, 'bar', 'qwerty')
在提取适当的值时，似乎需要花费大量的精力（而且它仍然不是特别健壮，而且指定得很糟糕）。有没有更好的方法来处理这些名称/值对？MATLAB附带的帮助函数是否有帮助？对此有帮助。有关更多信息，请参阅。我更喜欢国产锅炉铭牌代码，如下所示：
function TestExample(req1, req2, varargin)
for i = 1:2:length(varargin)
if strcmpi(varargin{i}, 'alphabet')
ALPHA = varargin{i+1};
elseif strcmpi(varargin{i}, 'cutoff')
CUTOFF = varargin{i+1};
%we need to remove these so seqlogo doesn't get confused
rm_inds = [rm_inds i, i+1]; %#ok<*AGROW>
elseif strcmpi(varargin{i}, 'colors')
colors = varargin{i+1};
rm_inds = [rm_inds i, i+1];
elseif strcmpi(varargin{i}, 'axes_handle')
handle = varargin{i+1};
rm_inds = [rm_inds i, i+1];
elseif strcmpi(varargin{i}, 'top-n')
TOPN = varargin{i+1};
rm_inds = [rm_inds i, i+1];
elseif strcmpi(varargin{i}, 'inds')
npos = varargin{i+1};
rm_inds = [rm_inds i, i+1];
elseif strcmpi(varargin{i}, 'letterfile')
LETTERFILE = varargin{i+1};
rm_inds = [rm_inds i, i+1];
elseif strcmpi(varargin{i}, 'letterstruct')
lo = varargin{i+1};
rm_inds = [rm_inds i, i+1];
end
end
功能测试示例（req1、REK2、varargin）
对于i=1:2：长度（varargin）
如果strcmpi（varargin{i}，'字母表'）
α=varargin{i+1}；
elseif strcmpi（varargin{i}，'截止'）
截止=varargin{i+1}；
%我们需要删除这些，这样seqlogo就不会混淆
rm_inds=[rm_inds i，i+1]；%#好啊
elseif strcmpi（varargin{i}，'颜色'）
颜色=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
elseif strcmpi（varargin{i}，'轴\手柄'）
handle=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
elseif strcmpi（varargin{i}，'top-n'）
TOPN=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
elseif strcmpi（varargin{i}，'inds'）
npos=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
elseif strcmpi（varargin{i}，'letterfile'）
lettfile=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
elseif strcmpi（varargin{i}，'letterstruct'）
lo=varargin{i+1}；
rm_inds=[rm_inds i，i+1]；
结束
结束
Will我更喜欢使用结构作为选项。这为您提供了存储选项和定义选项的简单方法。而且，整个系统变得相当紧凑
function example(varargin)
%# define defaults at the beginning of the code so that you do not need to
%# scroll way down in case you want to change something or if the help is
%# incomplete
options = struct('firstparameter',1,'secondparameter',magic(3));
%# read the acceptable names
optionNames = fieldnames(options);
%# count arguments
nArgs = length(varargin);
if round(nArgs/2)~=nArgs/2
error('EXAMPLE needs propertyName/propertyValue pairs')
end
for pair = reshape(varargin,2,[]) %# pair is {propName;propValue}
inpName = lower(pair{1}); %# make case insensitive
if any(strcmp(inpName,optionNames))
%# overwrite options. If you want you can test for the right class here
%# Also, if you find out that there is an option you keep getting wrong,
%# you can use "if strcmp(inpName,'problemOption'),testMore,end"-statements
options.(inpName) = pair{2};
else
error('%s is not a recognized parameter name',inpName)
end
end
阅读这个问题。别忘了阅读评论部分…-您将看到，对于这个主题有很多不同的方法。它们都是有效的，因此选择一种更喜欢的方法实际上是个人品味和可维护性的问题。我可以为此唠叨几个小时，但对于一般的Matlab签名处理仍然没有一个良好的格式塔视图。但这里有几条建议 首先，采用自由放任的方法验证输入类型。相信打电话的人。如果您真的想要强类型测试，那么您需要一种像Java这样的静态语言。试着在Matlab中的每一个地方都强制执行类型安全性，最终你将有一大部分的LOC和执行时间用于运行时类型测试和userland中的强制，这将极大地提高Matlab的能力和开发速度。我通过艰苦的方式学会了这一点 对于API签名（从其他函数调用的函数，而不是从命令行调用的函数），考虑使用单个ARGS参数而不是Valgin。然后，它可以在多个参数之间传递，而无需将其转换为varargin签名的逗号分隔列表。正如Jonas所说，结构非常方便。结构和n-by-2{name，value；…}单元格之间也有一个很好的同构关系，您可以设置一对函数，在函数内部将它们转换为它希望在内部使用的任何一个
function example(args)
%EXAMPLE
%
% Where args is a struct or {name,val;...} cell array
function out = my_example_function(varargin)
%MY_EXAMPLE_FUNCTION Example function
% No type handling
args = parsemyargs(varargin, {
'Stations' {'ORD','SFO','LGA'}
'Reading' 'Min Temp'
'FromDate' '1/1/2000'
'ToDate' today
'Units' 'deg. C'
});
fprintf('\nArgs:\n');
disp(args);
% With type handling
typed_args = parsemyargs(varargin, {
'Stations' {'ORD','SFO','LGA'} 'cellstr'
'Reading' 'Min Temp' []
'FromDate' '1/1/2000' 'datenum'
'ToDate' today 'datenum'
'Units' 'deg. C' []
});
fprintf('\nWith type handling:\n');
disp(typed_args);
% And now in your function body, you just reference stuff like
% args.Stations
% args.FromDate
function out=parsemyargs（args，默认值）
%PARSEMYARGS Arg解析器帮助程序
%
%out=parsemyargs（Args，默认值）
%
%解析名称/值参数对。
%
%Args是您将varargin传递给的对象。可能是
%
%ArgTypes是参数名称、默认值和可选值的列表
%输入的参数类型。它是一个n-by-1、n-by-2或n-by-3单元
%在这些表格中：
%{Name；…}
%{Name，DefaultValue；…}
%{Name，DefaultValue，Type；…}
%您还可以传递转换为第一种形式的结构，或
%包含名称/值对的单元格行向量，如
%{Name，DefaultValue，Name，DefaultValue，…}
%仅支持行向量，因为当二维形式
%最多有3列。如果可能有更多的专栏，我想你会
%必须要求2-d形式，因为4元素长向量
%不清楚是记录在案，还是两条记录加两条记录
%省略列。
%
%返回struct。
%
%这很慢-不要使用将调用的名称/值签名函数
%在紧密的循环中。
args=结构化（args）；
默认值=解析默认值（默认值）；
%如果你想的话，你可以把这个案子正常化。我建议你不要这样做；这是一个运行时成本
%还有一个潜在的不一致性来源。
%[args，defaults]=以某种方式规范化案例（args，defaults）；
out=合并参数（参数，默认值）；
%%
函数out=parse_默认值（x）
%PARSE_DEFAULTS解析默认的arg spec结构
%
%返回形式为{Name，DefaultValue，Type；..}的n-by-3 cellrec。
如果是构造（x）
if~isscalar（x）
错误（'结构默认值必须是标量'
function out = parsemyargs(args, defaults)
%PARSEMYARGS Arg parser helper
%
% out = parsemyargs(Args, Defaults)
%
% Parses name/value argument pairs.
%
% Args is what you pass your varargin in to. It may be
%
% ArgTypes is a list of argument names, default values, and optionally
% argument types for the inputs. It is an n-by-1, n-by-2 or n-by-3 cell in one
% of these forms forms:
% { Name; ... }
% { Name, DefaultValue; ... }
% { Name, DefaultValue, Type; ... }
% You may also pass a struct, which is converted to the first form, or a
% cell row vector containing name/value pairs as
% { Name,DefaultValue, Name,DefaultValue,... }
% Row vectors are only supported because it's unambiguous when the 2-d form
% has at most 3 columns. If there were more columns possible, I think you'd
% have to require the 2-d form because 4-element long vectors would be
% ambiguous as to whether they were on record, or two records with two
% columns omitted.
%
% Returns struct.
%
% This is slow - don't use name/value signatures functions that will called
% in tight loops.
args = structify(args);
defaults = parse_defaults(defaults);
% You could normalize case if you want to. I recommend you don't; it's a runtime cost
% and just one more potential source of inconsistency.
%[args,defaults] = normalize_case_somehow(args, defaults);
out = merge_args(args, defaults);
%%
function out = parse_defaults(x)
%PARSE_DEFAULTS Parse the default arg spec structure
%
% Returns n-by-3 cellrec in form {Name,DefaultValue,Type;...}.
if isstruct(x)
if ~isscalar(x)
error('struct defaults must be scalar');
end
x = [fieldnames(s) struct2cell(s)];
end
if ~iscell(x)
error('invalid defaults');
end
% Allow {name,val, name,val,...} row vectors
% Does not work for the general case of >3 columns in the 2-d form!
if size(x,1) == 1 && size(x,2) > 3
x = reshape(x, [numel(x)/2 2]);
end
% Fill in omitted columns
if size(x,2) < 2
x(:,2) = {[]}; % Make everything default to value []
end
if size(x,2) < 3
x(:,3) = {[]}; % No default type conversion
end
out = x;
%%
function out = structify(x)
%STRUCTIFY Convert a struct or name/value list or record list to struct
if isempty(x)
out = struct;
elseif iscell(x)
% Cells can be {name,val;...} or {name,val,...}
if (size(x,1) == 1) && size(x,2) > 2
% Reshape {name,val, name,val, ... } list to {name,val; ... }
x = reshape(x, [2 numel(x)/2]);
end
if size(x,2) ~= 2
error('Invalid args: cells must be n-by-2 {name,val;...} or vector {name,val,...} list');
end
% Convert {name,val, name,val, ...} list to struct
if ~iscellstr(x(:,1))
error('Invalid names in name/val argument list');
end
% Little trick for building structs from name/vals
% This protects cellstr arguments from expanding into nonscalar structs
x(:,2) = num2cell(x(:,2));
x = x';
x = x(:);
out = struct(x{:});
elseif isstruct(x)
if ~isscalar(x)
error('struct args must be scalar');
end
out = x;
end
%%
function out = merge_args(args, defaults)
out = structify(defaults(:,[1 2]));
% Apply user arguments
% You could normalize case if you wanted, but I avoid it because it's a
% runtime cost and one more chance for inconsistency.
names = fieldnames(args);
for i = 1:numel(names)
out.(names{i}) = args.(names{i});
end
% Check and convert types
for i = 1:size(defaults,1)
[name,defaultVal,type] = defaults{i,:};
if ~isempty(type)
out.(name) = needa(type, out.(name), type);
end
end
%%
function out = needa(type, value, name)
%NEEDA Check that a value is of a given type, and convert if needed
%
% out = needa(type, value)
% HACK to support common 'pseudotypes' that aren't real Matlab types
switch type
case 'cellstr'
isThatType = iscellstr(value);
case 'datenum'
isThatType = isnumeric(value);
otherwise
isThatType = isa(value, type);
end
if isThatType
out = value;
else
% Here you can auto-convert if you're feeling brave. Assumes that the
% conversion constructor form of all type names works.
% Unfortunately this ends up with bad results if you try converting
% between string and number (you get Unicode encoding/decoding). Use
% at your discretion.
% If you don't want to try autoconverting, just throw an error instead,
% with:
% error('Argument %s must be a %s; got a %s', name, type, class(value));
try
out = feval(type, value);
catch err
error('Failed converting argument %s from %s to %s: %s',...
name, class(value), type, err.message);
end
end
function argStruct = NameValuePairToStruct(defaults, varargin)
%NAMEVALUEPAIRTOSTRUCT Converts name/value pairs to a struct.
%
% ARGSTRUCT = NAMEVALUEPAIRTOSTRUCT(DEFAULTS, VARARGIN) converts
% name/value pairs to a struct, with defaults. The function expects an
% even number of arguments to VARARGIN, alternating NAME then VALUE.
% (Each NAME should be a valid variable name.)
%
% Examples:
%
% No defaults
% NameValuePairToStruct(struct, ...
% 'foo', 123, ...
% 'bar', 'qwerty', ...
% 'baz', magic(3))
%
% With defaults
% NameValuePairToStruct( ...
% struct('bar', 'dvorak', 'quux', eye(3)), ...
% 'foo', 123, ...
% 'bar', 'qwerty', ...
% 'baz', magic(3))
%
% See also: inputParser
nArgs = length(varargin);
if rem(nArgs, 2) ~= 0
error('NameValuePairToStruct:NotNameValuePairs', ...
'Inputs were not name/value pairs');
end
argStruct = defaults;
for i = 1:2:nArgs
name = varargin{i};
if ~isvarname(name)
error('NameValuePairToStruct:InvalidName', ...
'A variable name was not valid');
end
argStruct = setfield(argStruct, name, varargin{i + 1}); %#ok<SFLD>
end
end
%# old versions
which -all statgetargs
which -all internal.stats.getargs
which -all internal.stats.parseArgs
%# current one, as of R2014a
which -all statslib.internal.parseArgs
function varargout = parseArgs(pnames, dflts, varargin)
%
% [A,B,...] = parseArgs(PNAMES, DFLTS, 'NAME1',VAL1, 'NAME2',VAL2, ...)
% PNAMES : cell array of N valid parameter names.
% DFLTS : cell array of N default values for these parameters.
% varargin : Remaining arguments as name/value pairs to be parsed.
% [A,B,...]: N outputs assigned in the same order as the names in PNAMES.
%
% [A,B,...,SETFLAG] = parseArgs(...)
% SETFLAG : structure of N fields for each parameter, indicates whether
% the value was parsed from input, or taken from the defaults.
%
% [A,B,...,SETFLAG,EXTRA] = parseArgs(...)
% EXTRA : cell array containing name/value parameters pairs not
% specified in PNAMES.
function my_plot(x, varargin)
%# valid parameters, and their default values
pnames = {'Color', 'LineWidth', 'LineStyle', 'Title'};
dflts = { 'r', 2, '--', []};
%# parse function arguments
[clr,lw,ls,txt] = internal.stats.parseArgs(pnames, dflts, varargin{:});
%# use the processed values: clr, lw, ls, txt
%# corresponding to the specified parameters
%# ...
end
>> my_plot(data) %# use the defaults
>> my_plot(data, 'linestyle','-', 'Color','b') %# any order, case insensitive
>> my_plot(data, 'Col',[0.5 0.5 0.5]) %# partial name match
%# unrecognized parameter
>> my_plot(x, 'width',0)
Error using [...]
Invalid parameter name: width.
%# bad parameter
>> my_plot(x, 1,2)
Error using [...]
Parameter name must be text.
%# wrong number of arguments
>> my_plot(x, 'invalid')
Error using [...]
Wrong number of arguments.
%# ambiguous partial match
>> my_plot(x, 'line','-')
Error using [...]
Ambiguous parameter name: line.
function argtest(varargin)
a = 1;
for ii=1:length(varargin)/2
[~] = evalc([varargin{2*ii-1} '=''' num2str(varargin{2*ii}) '''']);
end;
disp(a);
who
% Overlay default fields with input fields
% Good for option management
% Arguments
% $opts - Default options
% $optsIn - Input options
% Can be struct(), cell of {name, value, ...}, or empty []
% $recurseStructs - Applies optOverlay to any existing structs, given new
% value is a struct too and both are 1x1 structs
% Output
% $opts - Outputs with optsIn values overlayed
function [opts] = optOverlay(opts, optsIn, recurseStructs)
if nargin < 3
recurseStructs = false;
end
isValid = @(o) isstruct(o) && length(o) == 1;
assert(isValid(opts), 'Existing options cannot be cell array');
assert(isValid(optsIn), 'Input options cannot be cell array');
if ~isempty(optsIn)
if iscell(optsIn)
optsIn = struct(optsIn{:});
end
assert(isstruct(optsIn));
fields = fieldnames(optsIn);
for i = 1:length(fields)
field = fields{i};
assert(isfield(opts, field), 'Field does not exist: %s', field);
newValue = optsIn.(field);
% Apply recursion
if recurseStructs
curValue = opts.(field);
% Both values must be proper option structs
if isValid(curValue) && isValid(newValue)
newValue = optOverlay(curValue, newValue, true);
end
end
opts.(field) = newValue;
end
end
end
function example(varargin)
defaults = struct('A',1, 'B',magic(3)); %define default values
params = struct(varargin{:});
for f = fieldnames(defaults)',
if ~isfield(params, f{1}),
params.(f{1}) = defaults.(f{1});
end
end
%now just access them as params.A, params.B
function argStruct = getnargs(varargin, defaults, restrict_flag)
%GETNARGS Converts name/value pairs to a struct (this allows to process named optional arguments).
%
% ARGSTRUCT = GETNARGS(VARARGIN, DEFAULTS, restrict_flag) converts
% name/value pairs to a struct, with defaults. The function expects an
% even number of arguments in VARARGIN, alternating NAME then VALUE.
% (Each NAME should be a valid variable name and is case sensitive.)
% Also VARARGIN should be a cell, and defaults should be a struct().
% Optionally: you can set restrict_flag to true if you want that only arguments names specified in defaults be allowed. Also, if restrict_flag = 2, arguments that aren't in the defaults will just be ignored.
% After calling this function, you can access your arguments using: argstruct.your_argument_name
%
% Examples:
%
% No defaults
% getnargs( {'foo', 123, 'bar', 'qwerty'} )
%
% With defaults
% getnargs( {'foo', 123, 'bar', 'qwerty'} , ...
% struct('foo', 987, 'bar', magic(3)) )
%
% See also: inputParser
%
% Authors: Jonas, Richie Cotton and LRQ3000
%
% Extract the arguments if it's inside a sub-struct (happens on Octave), because anyway it's impossible that the number of argument be 1 (you need at least a couple, thus two)
if (numel(varargin) == 1)
varargin = varargin{:};
end
% Sanity check: we need a multiple of couples, if we get an odd number of arguments then that's wrong (probably missing a value somewhere)
nArgs = length(varargin);
if rem(nArgs, 2) ~= 0
error('NameValuePairToStruct:NotNameValuePairs', ...
'Inputs were not name/value pairs');
end
% Sanity check: if defaults is not supplied, it's by default an empty struct
if ~exist('defaults', 'var')
defaults = struct;
end
if ~exist('restrict_flag', 'var')
restrict_flag = false;
end
% Syntactic sugar: if defaults is also a cell instead of a struct, we convert it on-the-fly
if iscell(defaults)
defaults = struct(defaults{:});
end
optionNames = fieldnames(defaults); % extract all default arguments names (useful for restrict_flag)
argStruct = defaults; % copy over the defaults: by default, all arguments will have the default value.After we will simply overwrite the defaults with the user specified values.
for i = 1:2:nArgs % iterate over couples of argument/value
varname = varargin{i}; % make case insensitive
% check that the supplied name is a valid variable identifier (it does not check if the variable is allowed/declared in defaults, just that it's a possible variable name!)
if ~isvarname(varname)
error('NameValuePairToStruct:InvalidName', ...
'A variable name was not valid: %s position %i', varname, i);
% if options are restricted, check that the argument's name exists in the supplied defaults, else we throw an error. With this we can allow only a restricted range of arguments by specifying in the defaults.
elseif restrict_flag && ~isempty(defaults) && ~any(strmatch(varname, optionNames))
if restrict_flag ~= 2 % restrict_flag = 2 means that we just ignore this argument, else we show an error
error('%s is not a recognized argument name', varname);
end
% else alright, we replace the default value for this argument with the user supplied one (or we create the variable if it wasn't in the defaults and there's no restrict_flag)
else
argStruct = setfield(argStruct, varname, varargin{i + 1}); %#ok<SFLD>
end
end
end
function varspull(s)
% Import variables in a structures into the local namespace/workspace
% eg: s = struct('foo', 1, 'bar', 'qwerty'); varspull(s); disp(foo); disp(bar);
% Will print: 1 and qwerty
%
%
% Author: Jason S
%
for n = fieldnames(s)'
name = n{1};
value = s.(name);
assignin('caller',name,value);
end
end
function y = func(x, y, varargin)
[u, v] = process_options(varargin,
'u', 0,
'v', 1);
function htmldlg(varargin)
names = {'url','html','title'};
defaults = {[],[],'Padaco Help'};
[url, html,titleStr] = parsepvpairs(names,defaults,varargin{:});
%... code to create figure using the parsed input values
end