Sorta

Sorta is used to sort arrays of single-dimensioned variables.

Syntax

Sorta ARRAY_LIST
Sorta NUMBER ARRAY_LIST
Sorta ARRAY_LIST Order By EXPRESSION_LIST
Sorta NUMBER ARRAY_LIST Order By EXPRESSION_LIST
Sorta ARRAY_LIST ASCDES
Sorta NUMBER ARRAY_LIST ASCDES
Sorta ARRAY_LIST Order By EXPRESSION_LIST ASCDES
Sorta NUMBER ARRAY_LIST Order By EXPRESSION_LIST ASCDES

• NUMBER is an integer expression that gives the number of positions to be sorted. It must be strictly positive. If not given by the syntax, all the elements will be sorted.
• ARRAY_LIST is a list of arrays variable (at least one) separated by commas.
• EXPRESSION_LIST is a list of expressions using elements of the arrays with the [S]indice system variable used as the current index.
• ASCDES is the Asc or Desc keyword (ascending or descending order). The ascending order is used by default. This option is used on all expression lists or on all the columns.

Example

You have three arrays called COMPOSER(1..11), FIRST_NAME(1..11), and BIRTH_YEAR(1..11). In this example, you can see the original order and the final order after the Sorta instruction, depending on the syntax:

Sorta 10 BIRTH_YEAR, COMPOSER, FIRST_NAME

Sorta BIRTH_YEAR, COMPOSER, FIRST_NAME

Sorta 10 COMPOSER,FIRST_NAME,BIRTH_YEAR Order By COMPOSER(indice+1), -BIRTH_YEAR(indice+1), FIRST_NAME(indice+1)

Sorta 10 COMPOSER,FIRST_NAME,BIRTH_YEAR Order By FIRST_NAME(indice+1),NAME(indice+1),-BIRTH_YEAR(indice+1) Desc

Comments

• The Sorta instruction is used to sort single-dimension elements of arrays. If the number of elements is not specified, the sort is performed on a number of elements defined by the smallest dimension of the arrays present.
• The Sorta instruction does not work on collections in class instances.
• The sort is ascending by default. However, it is possible to sort an array on a numeric field in descending order by multiplying this field by -1.
• When there is no Order By clause, the sort is performed in the order of the first array. If elements in this array are equal, it will be performed in the order of the second array, and so forth for all the arrays to be sorted.
• If an Order By clause is specified, the sort is done in the order of the first expression, the second if some values are the same, and so forth.
• The algorithms used make the sort non-conservative. This means that if elements in the ordering expressions are the same for two index values, you cannot know in which order they will appear in the results for other arrays.
• The [S]indice value starts with 0. Thus, if an array that has an index starting with 1 is sorted with an expression, this expression must use indice+1 and not indice.

Example of unexpected result when indice is used for arrays starting at index 1:

Sorta 5 COMPOSER,FIRST_NAME, BIRTH_YEAR Using -BIRTH_YEAR(indice),COMPOSER(indice)

The reason is that the array was sorted in the order of the following expressions:

• For SCHUBERT (line 2 before the sort), -BIRTH_YEAR(1) is -1804
• For SCHUBERT (line 5 before the sort), -BIRTH_YEAR(4) is -1770
• For STRAUSS (line 3 before the sort), -BIRTH_YEAR(2) is -1685 and FIRST_NAME(2) is "Johann"
• For BACH (line 2 before the sort), -BIRTH_YEAR(1) is -1685 and FIRST_NAME(1) is "Georg"
• For BEETHOVEN (line 1 before the sort), -BIRTH_YEAR() is undefined (0 by default)

Associated errors

See also

• Insa
• Dela