miva_array_filter_ref()

    
Also See:   miva_array_binarysearch miva_array_clear miva_array_collapse miva_array_copy miva_array_copy_ref miva_array_delete miva_array_deserialize miva_array_elements miva_array_filter miva_array_find miva_array_insert miva_array_insert_ref miva_array_insert_var miva_array_max miva_array_merge miva_array_merge_ref miva_array_min miva_array_next miva_array_pop miva_array_pop_ref miva_array_previous miva_array_search miva_array_serialize miva_array_shift miva_array_shift_ref miva_array_sort miva_element_exists miva_member_exists miva_struct_members miva_struct_member_callback miva_struct_merge miva_struct_merge_ref

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Iterate through an array starting at a given offset, execute a filter expression against each element, and create a new member with references to the members in the output array. See also miva_array_filter.
Syntax 
miva_array_filter_ref( array var, offset, element var, filter_expression, output var )
Return value: Count of output array elements.
  • array var = Source array of structures.
  • offset = index in the array to start filtering from.
  • element var = Name of a variable to reference in the filter expression.
  • filter_expression = Text of an expression to execute based on the individual array element.
  • output var = Output array of all structures that tested true in the filter expression.

In this example the array l.facets is filtered into a new array l.enabled_facets by reference. Reference means that l.enabled_facets does not contain a copy of the filtered records, but a pointer to the original record, this is faster and uses less memory than miva_array_filter( )

miva_array_filter_ref( l.facets, 1, l.facet, 'NOT ISNULL l.facet:display', l.enabled_facets )'

The example code below is a representation (not the actual code) of what is going on within the function to clarify the parameters.

  • The array l.facets contains an aggregate data structure in the form facets[n]:members
  • The offest of 1 means to start filtering at the first record.
  • The element l.facet, is the iterator or variable containing each array record used in the filter_expression
  • The filter_expression 'NOT ISNULL l.facet:display', is a string containing the conditional expression testing each record in l.facets. If the result is true the record is added to the output array.
  • The output l.enabled_facets is a new array containing the filtered record set.
<MvFOREACH ITERATOR = "l.facet" ARRAY = "l.facets">
  <MvIF EXPR="{ NOT ISNULL l.facet:display }">
    <MvASSIGN NAME="l.return_count" VALUE="{ miva_array_insert_ref( l.enabled_facets, l.facet, -1 ) }">
  </MvIF>
</MvFOREACH> 
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