B4P Reference

Function Names

middle , middle include , middle until , middle until include

Description

This function extracts a middle part of the set either with two element position numbers or matching elements or a combination of both.

Call as: function

Restrictions

Indirect parameter passing is disabled

Parameter count

Min 3

Parameters

No.	Type	Description
1 input	set	input set Attention: If 1st parameter is not a set, please refer to middle [string function] instead.
2 input	numeral	starting element position Positive: Begin with specified element (0 = 1st element, 1 = 2nd element, etc.) Larger than number of elements: empty set Negative: Starting position counted from right to left, e.g. -1 = last element Smaller than minus number of set elements in the set: Begins with 1st element The function name ending '... include' will be ignored.
Alt. 2 input	set	starting matching elements Function middle ...: Middle part of the set begins after the matching element. Function middle include ...: Middle part of the set begins including the matching element. Empty sets are interprested as per se found. If this function parameter contains 2 or more elements, then the set will be compared with all elements and the first match with any of these elements will apply. Function name ending ... last match: Looks for the last matching element in the set and not the first one.
3 input	numeral	element count or ending element position For function names middle until, this parameter contains the ending element position. Negative numbers count from right to left: -1 = last set element included, -2 = 2nd last element included. Element positions before the starting position of found matching element will return empty sets. For function names not containing until, this parameter contains the element count. 0 and negative numbers return empty sets. The function name ending '... include' will be ignored.
Alt. 3 input	set	ending matching elements Function outside ...: 2nd part of the set begins including the ending matching elemetn. Function outside exclude ...: 2nd part of the set begins after the ending matching element. Empty sets means no further matches and the full original set is returned. Attention: The function names ending outside until combined with matching elements provided will assert errors. If this function parameter contains 2 or more elements, then the set will be compared with all elements and the first match with any of these elements will apply. Function name ending ... last match: Looks for the last matching element in the set and not the first one. Empty sets are interprested as per se found.
Opt. 4+ io	set	follower Other sets in addition to the one provided as the first function parameter can be extracted in the same same way. Add any number of additional set variables. They will be manipulated at the exact same positions as the returned value.

Return value

Type	Description
set	Extracted subset

Examples

               set[] = { the, taste, of, the, 12, coffees, '!' };



               echo( middle( set[], 4,  2 ), " / ", middle until( set[], 1, 5 ) );

               echo( middle( set[], -3, 2 ), " / ",  middle until( set[], -6, -2 ) );

               echo;

               echo( middle( set[],  99, 3 ), " / ",  middle until ( set[],  99, 3 ) ); // empty sets

               echo( middle( set[], -99, 3 ), " / ",  middle until ( set[], -99, 3 ) ); // the taste of / ... the

               echo;

               echo( middle( set[], {taste}, 4 ), " / ", middle include( set[], {taste}, 4 ) ); // 4 elements in both cases

               echo( middle until( set[], {taste}, -2 ), " / ", middle until include( set[], {taste}, -2 ) );

               echo( middle ( set[], {taste}, {coffees} ), " / ", middle include( set[], {taste}, {coffees} ) );



               echo( middle ( set[], {}, {coffees} ), " / ", middle include( set[], {taste}, {} ) );

               echo( middle ( {}, {}, {coffees} ), " / ", middle include( {}, {taste}, {} ) ); // empty sets

               echo;

               echo( "Demonstrate the follower feature: ");



               set2[] = { A, fragrance, coming, from, 120, espressos, '!' };

               set3[] = { Der, Geschmack, kommt, von, 120, Tassen Kaffee, '!' };



               echo( "Extraction 1: ", middle( set[], {of}, 3, set2[], set3[] ) );

               echo( "Extraction 2: ", set2[] );

               echo( "Extraction 3: ", set3[] );

Output

{12,'coffees'} / {'taste','of','the',12,'coffees'}
{12,'coffees'} / {'taste','of','the',12,'coffees'}

{} / {}
{'the','taste','of'} / {'the','taste','of','the'}

{'of','the',12,'coffees'} / {'taste','of','the',12}
{'of','the',12,'coffees'} / {'taste','of','the',12,'coffees'}
{'of','the',12} / {'taste','of','the',12,'coffees'}
{'the','taste','of','the',12} / {}
{} / {}

Demonstrate the follower feature: 
Extraction 1: {'the',12,'coffees'}
Extraction 2: {'from',120,'espressos'}
Extraction 3: {'von',120,'Tassen Kaffee'}

Try it yourself: Open LIB_Function_middle_.b4p in B4P_Examples.zip. Decompress before use.

middle ... (set function)