<@UNION>
Syntax
<@UNION ARRAY1=arrayVarName1 ARRAY2=arrayVarName2 [COLS=compCol [compType]] [SCOPE1=scope1] [SCOPE2=scope2]>
Description
Returns the union of two arrays. The union consists of the combination of both arrays, with duplicates removed. Duplicates are found based on the values of the specified columns, checked using the specified comparison type.
The two input arrays are not modified. To store the result of this meta tag in a variable, use a variable assignment.
Note:
To join two arrays without
removing duplicates, use the <@ADDROWS> tag.
The ARRAY1 and ARRAY2 attributes specify the names of variables containing arrays. The arrays must contain the same number of columns. The optional COLS attribute specifies the column(s) to consider when eliminating duplicates: the columns are specified using column numbers or names, with an optional comparison type (compType). The arrays must have the same number of columns; otherwise, an error is generated.
Valid comparison types are SMART (the default), DICT, ALPHA and NUM. DICT compares columns alphabetically, irrespective of case. ALPHA performs a case-sensitive comparison. NUM compares columns numerically. SMART checks whether values are numeric or alphabetic and performs a NUM or DICT comparison.
If no COLS attribute is specified, the elimination of duplicates is accomplished via a SMART comparison type that examines all columns in a row.
The SCOPE1 and SCOPE2 attributes specify the scope of the variables specified by ARRAY1 and ARRAY2, respectively. If the attribute is not specified, the default scoping rules are used.
Meta tags are permitted in any of the attributes.
Examples
- If the variable old_items
contains the following array:
blue green orange
and the array new_items contains the following:
orange pink blue pink <@UNION ARRAY1="old_items" ARRAY2="new_items"> returns:
blue green orange pink - If the variable test contains
the following array:
1 a a 2 b c 3 c c and the variable test2 contains:
1 a a 2 b b 3 c c 3.0 c c <@UNION ARRAY1="test" ARRAY2="test2"> returns:
1 a a 2 b c 3 c c 2 b b
- Variable usr1 contains the
following:
Gilbert Steve 1823-1344 $433.00 Brown Robert 5543-1233 $332.50 Brown Marsha 1122-5778 $541.00 Variable usr2 contains the following:
Kelly Herbert 5543-1443 $100.50 Brown Robert 6670-1123 $1123.75 MacDonald Bill 1551-0787 $150.75 To find the unique users in both arrays, you would find the union of the two arrays based on the first two columns.
<@UNION ARRAY1="usr1" ARRAY2="usr2" COLS="1, 2"> returns:
Gilbert Steve 1823-1344 $433.00 Brown Robert 6670-1123 $1123.75 * Brown Marsha 1122-5778 $541.00 Kelly Herbert 5543-1443 $100.50 MacDonald Bill 1551-0787 $150.75 * Tango returns just one of the rows that have the same values in the specified columns (1 and 2).
The values in columns 3 and 4 are ignored for the purpose of the union operation since COLS="1, 2" is specified.