Create Unique Interaction Variables 1.0

function data_set = create_interaction_variables(data_set,vars,range_nways,separator,max_varname_length)% create_interaction_variables%% for Matlab R13+% version 1.1 (April 2012)% (c) Brian Weidenbaum% website: http://www.BrianWeidenbaum.com/.%%% OUTPUT: your dataset (or a dataset based on your matrix), updated with new, aptly-named *unique* interaction variables,% ranging from at least 2 to any number the user specifies%% INPUTS (** = OPTIONAL)% input name: (input datatype/s) -- description%% data_set: (dataset OR matrix) -- the data you want to alter%% **vars: (cell array of chars/numbers, OR vector of numbers, OR 'ALL') --% default: 'ALL'% the names of the variables you want to interact; alternatively, the column numbers of the variables you want to interact% OR, you can just say 'ALL' to include all variables automatically%% **range_nways (vector OR 'MAX') --% default: 2% the range of numbers of variables to include in the interaction terms generated by this function% alternatively, just type 'MAX' to use 2 variables to the maximum possible number of vars%% **separator (char) --% default: '_'% the separator string you want to use to divide the% variable names that contributed to a new interaction variable. Default% is '_'. E.g., by default, an interaction between Var1 and Var2 will be% named 'Var1_Var2'.%% **max_varname_length (number) --% default: 63% the maximum length of the newly created interaction terms' variable names.% Any dynamically generated variable names (e.g. 'Var1_Var2') that exceed this number will be excluded from the new dataset.% You should set max_varname_length according to the database you plan to use with your data--% e.g., if you only want to use this data in MATLAB, you should set max_varname_length=63 (the maximum length supported by the dataset class,% but if you plan to export your data to Oracle, you should set it to around 30%%%% EXAMPLES%% You have a dataset with 3 variables: a, b, and c.% You want to create interaction terms, up to 3 ways, for all of your variables.% You type:% new_dataset = create_interaction_variables(old_dataset,'all','max');% new_dataset will contain:% a.*b, named 'a_b'% a.*c, named 'a_c'% b.*c, named 'b_c'% and a.*b.*c, named 'a_b_c',% plus all original variables.% It will NOT contain b.*a, c.*a, etc because these are not unique combos.%% You have a dataset with 3 variables: a, b, and c.% You want to create interaction terms, up to 2 ways, only for columns 2 and 3.% You type:% new_dataset = create_interaction_variables(old_dataset,[2 3],2);% new_dataset will contain only b.*c,% plus all original variables.%% You have a dataset with 3 variables: a, b, and c.% You want to create interaction terms, up to 2 ways, only for 'a' and 'c'.% You type:% new_dataset = create_interaction_variables(old_dataset,{'a','c'},2);% new_dataset will contain only a.*c,% plus all original variables.%% You have a dataset with 3 variables: a, b, and c.% You want to create interaction terms, ONLY 3 ways, only for all vars.% You type:% new_dataset = create_interaction_variables(old_dataset,'all',3);% new_dataset will contain only a .* b .* c,% plus all original variables.

Requirements:	No special requirements
Platforms:	Matlab
Keyword:	Created,  Default,  Dynamically,  Exceed,  Length,  Max Varname Length,  Named,  Newly,  Var Var
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