undef EXPR
undef
Undefines the value of EXPR, which must be an lvalue. Use only on a
scalar value, an entire array, or a subroutine name (using "&"). (Using undef()
will probably not do what you expect on most predefined variables or
DBM list values, so don't do that.) Always returns the undefined value. You can omit
the EXPR, in which case nothing is undefined, but you still get an
undefined value that you could, for instance, return from a
subroutine. Examples:
undef $foo;
undef $bar{'blurfl'};
undef @ary;
undef %assoc;
undef &mysub;
return (wantarray ? () : undef) if $they_blew_it;
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