gusucode.com > datatypes 工具箱matlab源码程序 > datatypes/@tabular/table2gidx.m
function [group,glabels,glocs] = table2gidx(a,avars,reduce)
% TABLE2GIDX Create group indices from table grouping variables.
% Copyright 2012-2016 The MathWorks, Inc.
% Default behavior is to leave out categories that are not actually present in
% the data of a categorical variable. Non-categorical variables _always_, in
% effect, do that.
try
if nargin < 3, reduce = true; end
a_data = a.data;
a_varnames = a.varDim.labels;
nrows = a.rowDim.length;
ngroupVars = length(avars);
if ngroupVars == 0 % if no grouping vars, create one group containing all observations
group = ones(nrows,1);
glocs = ones(min(nrows,1),1); % 1 if there are rows, 0x1 if not
glabels = {'All'};
elseif ngroupVars == 1
% Create an index vector based on the unique values of the grouping variable
if avars == 0 % the row labels
[group,glabels,glocs] = grp2idx(a.rowDim.labels,a.metaDim.labels{1},reduce);
else
[group,glabels,glocs] = grp2idx(a_data{avars},a_varnames{avars},reduce);
end
else % ngroupVars > 1
% Get integer group codes and names for each grouping variable
groups = zeros(nrows,ngroupVars);
names = cell(1,ngroupVars);
for j = 1:ngroupVars
[groups(:,j),names{j}] = grp2idx(a_data{avars(j)},a_varnames{avars(j)},reduce);
end
% Create an index vector based on the unique combinations of individual grouping variables
wasnan = any(isnan(groups),2);
group = NaN(size(wasnan));
groups(wasnan,:) = [];
[urows,glocs,gidx] = unique(groups,'rows','sorted');
ngroups = size(urows,1);
group(~wasnan) = gidx;
% Translate the NaN-reduced row indices back to the original rows
tmp = find(~wasnan); glocs = tmp(glocs);
gnames = cell(ngroups,ngroupVars);
for j = 1:ngroupVars
gnames(:,j) = names{j}(urows(:,j));
end
glabels = cell(ngroups,1);
for j = 1:ngroups
glabels{j} = strjoin(gnames(j,:),'_');
end
end
catch ME
throwAsCaller(ME)
end
%-------------------------------------------------------------------------------
function [gidx,gnames,gloc] = grp2idx(var,varName,reduce)
% GRP2IDX Create index vector from a grouping variable.
% [G,GN,GL] = GRP2IDX(S) creates an index vector G from the grouping variable
% S. S can be a categorical, numeric, or logical vector; a cell vector of
% character vectors; or a character matrix with each row representing a
% group label. G is a vector of integer values from 1 up to the number K
% of distinct groups. GN is a cell array of character vectors containing
% group labels. GN(G) reproduces S (aside from any differences in type).
% GL is a vector of indices into the first element of S for each group.
%
% GRP2IDX treats NaNs (numeric or logical), empty character vectors (char
% or cell array of character vectors), or <undefined> values
% (categorical) in S as missing values and returns NaNs in the
% corresponding rows of G. Neither GN nor GL include entries for missing
% values.
if ischar(var)
if isempty(var)
var = cell(0,1);
else
var = cellstr(var);
end
end
if ~iscolumn(var)
error(message('MATLAB:table:GroupingVarNotColumn'));
end
if isa(var,'categorical')
if reduce
[glevels,gloc,gidx] = unique(var);
if ~isempty(glevels) && isundefined(glevels(end)) % undefineds are sorted to end
notNaN = ~isundefined(glevels);
glevels = glevels(notNaN);
gloc = gloc(notNaN);
gidx(gidx > length(glevels)) = NaN; % other indices stay the same
end
gnames = cellstr(glevels);
else
gidx = double(var); % converts <undefined> to NaN
gnames = categories(var)';
[~,gloc] = ismember(1:length(gnames),gidx);
end
else
try
[glevels,gloc,gidx] = unique(var,'sorted');
catch ME
m = message('MATLAB:table:VarUniqueMethodFailed',varName);
throwAsCaller(addCause(MException(m.Identifier,'%s',getString(m)), ME));
end
if length(gidx) ~= length(var)
m = message('MATLAB:table:VarUniqueMethodFailedNumRows',varName);
throwAsCaller(MException(m.Identifier,'%s',getString(m)));
end
if isnumeric(var) || islogical(var)
% Handle NaN missing values: return NaN group indices
if ~isempty(glevels) && isnan(glevels(end)) % NaNs are sorted to end
notNaN = ~isnan(glevels);
glevels = glevels(notNaN);
gloc = gloc(notNaN);
gidx(gidx > length(glevels)) = NaN; % other indices stay the same
end
gnames = numericLabels(glevels);
elseif isdatetime(var)
% Handle NaT missing values: return NaT group indices
if ~isempty(glevels) && isnat(glevels(end)) % NaTs are sorted to end
notNaT = ~isnat(glevels);
glevels = glevels(notNaT);
gloc = gloc(notNaT);
gidx(gidx > length(glevels)) = NaN; % other indices stay the same
end
gnames = cellstr(glevels);
elseif isduration(var)
% Handle NaN missing values: return NaN group indices
if ~isempty(glevels) && isnan(glevels(end)) % NaNs are sorted to end
notNaN = ~isnan(glevels);
glevels = glevels(notNaN);
gloc = gloc(notNaN);
gidx(gidx > length(glevels)) = NaN; % other indices stay the same
end
gnames = cellstr(glevels);
elseif isa(var,'string')
% Handle empty strings, return NaN group indices
if ~isempty(glevels) && (glevels(1) == '')
notEmpty = ~(glevels == '');
nEmpty = length(glevels) - sum(notEmpty);
glevels = glevels(notEmpty,1);
gloc = gloc(notEmpty);
adjustIdx = [NaN(1,nEmpty) 1:length(glevels)]';
gidx = adjustIdx(gidx);
end
gnames = cellstr(glevels);
elseif iscell(var) % iscellstr enforced by unique above
% Handle empty string missing values: return NaN group indices
if ~isempty(glevels) && isempty(glevels{1}) % empty strings are sorted to beginning
notNaN = ~cellfun('isempty',glevels);
% All empties are treated as '', but defensively find the number of empty strings
nEmpty = length(glevels) - sum(notNaN);
glevels = glevels(notNaN);
gloc = gloc(notNaN);
adjustIdx = [NaN(1,nEmpty) 1:length(glevels)]';
gidx = adjustIdx(gidx);
end
gnames = glevels;
else
error(message('MATLAB:table:GroupTypeIncorrect'));
end
end
%-------------------------------------------------------------------------------
function gnames = numericLabels(glevels)
gl = full(glevels);
gnames = sprintfc('%d',gl); % a little less than 19 significant digits
ufmt = (fix(gl) == gl) & (gl > intmax('int64'));
gnames(ufmt) = sprintfc('%u',gl(ufmt)); % a little more than 19 significant digits
gfmt = (fix(gl) ~= gl)| (gl < intmin('int64')) | (gl > intmax('uint64'));
if any(gfmt)
gnames(gfmt) = sprintfc('%g',gl(gfmt)); % six significant digits
% If some values in the grouping variable differ by less than (about)
% 1e-6 (relative), add more digits to make the names unique.
if length(unique(gnames)) < length(gnames)
tryFmt = {'%.16g' '%.17g' '0x%bx'};
for i = 1:length(tryFmt)
gnames(gfmt) = sprintfc(tryFmt{i},gl(gfmt));
if length(unique(gnames)) == length(gnames), break; end
end
end
end