Function Names
deleteDescription
This function deletes the specified variable including all members if existing.
If an array member is deleted, (e.g. delete( a[2] );), then the remaining array members further down close up. Obviously, members of structures
can also be deleted.
Attention: If the function call is executed in a local varaible context (e.g inside a user-defined fuction or a B4P program called by another B4P
program using start() or include(), then attempting to delete a non-local variable asserts an exception.
You can circumvent this by deleting the global variable in a global context provided with the global() function.
example: global() delete ( a global variable [ ] );
Call as: procedure
Restrictions
Indirect parameter passing is disabled
Parameter count
Min. 1
Parameters
| No. | Type | Description |
|---|---|---|
| 1, ... code |
variable :string |
Variable name The affected variable will be deleted resp. their members deleted. |
Exceptions
Variable is protected
Attempting to delete global variable in local context
Attempting to delete system variables
Examples
values[] = { 0, 11, 22, 33, 44, 55, 66, 77, 88, 99 };
a[] = This is the base variable;
array( a[], values[] );
delete( a[4], a[2] ); // Deletes subscript 2 and 4. Good idea to work from bottom to top
for all variables( a[], v[] ) print( v[], " " ); echo ("Note: 22 and 44 are missing. OK.");
echo("Attention when deleting lower subscripts before upper ones");
array( a[], values[] );
delete( a[2], a[4] ); // Deletes subscript 2 and 5 (not 4, becuase member variables have shifted up)
for all variables( a[], v[] ) print( v[], " " ); echo ("Note: 22 and 55 are missing this time");
echo;
echo("And with structures:", new line);
structure( a[], { Cat, Dog, Bird, { Parrot, Parakeet }, Rat, Mouse, Elephant, Zebra },
{ Katze, Hund, Vogel, { Papagei, Sittich }, Ratte, Maus, Elefant, Zebra } );
delete( a[Zebra]);
delete( a[Bird], a[Elephant], a[Cat] );
delete( a[Dinosaur] );
// B4P issues no error message if attempting to delete nonexisting variables,
// assuming they have already been deleted
see(a[]); // Dog Rat Mouse
delete(a[] );
echo( "Variable a[] existing? ", existing(a[]) );
Output
0 11 33 55 66 77 88 99 Note: 22 and 44 are missing. OK.
Attention when deleting lower subscripts before upper ones
0 11 33 44 66 77 88 99 Note: 22 and 55 are missing this time
And with structures:
a[] This is the base variable (softquoted string,full access)
Dog Hund (softquoted string,full access)
Mouse Maus (softquoted string,full access)
Rat Ratte (softquoted string,full access)
Variable a[] existing? false