Expressions And Operators: List
This intrinsic function assigns zero or more elements of its source to the corresponding target variable(s). It returns a copy of the source. For example:
$v = vec[10, 20, 30, 40]; list($_, $b, $_, $d) = $v;
When the source is a vec, the element having an
int key of 0 is assigned to the first target variable, the element having an
of 1 is assigned to the second target variable, and so on, until all target variables have been assigned.
$_ is used as a target variable, the value of the corresponding source element is ignored; no assignment takes place.
If the source elements and the target variables overlap in any way, the behavior is unspecified.
Here is an example of a source tuple:
list($x1, $x2, $x3) = tuple(123, "red", tuple(2.5, 999));
list($y1, $y2, list($y3, $y4)) = tuple(123, "red", tuple(2.5, 999));
Here, the target contains a nested list, in which case, elements 0 and 1 of the nested tuple are assigned to