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<@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 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 1
  Brown	Marsha	1122-5778	$541.00
  Kelly	Herbert	5543-1443	$100.50
  MacDonald	Bill	1551-0787	$150.75

  1 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.

See Also

<@ADDROWS>
<@DISTINCT>
<@FILTER>
<@INTERSECT>
<@SORT>

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