array_select_relative
Returns an array element in a position relative to a given value. This is useful for sequentially selecting values from an array based on a current value.
// Move forwards {+1} through a list of colors
color = select_relative(color, +1, [c_red, c_orange, c_yellow, c_green, c_blue]);In the above example, if the current value of color is c_orange, then its
new value would be set to the next value in the list, c_yellow.
// Or move backwards {-1} through a list of colors
color = select_relative(color, -1, [c_red, c_orange, c_yellow, c_green, c_blue]);If a relative position is beyond the range of given choices, the position is clamped
to be within range. In the second example, if the current value of color is c_red,
then it would keep its value because c_red is the first value in the list.
If the current value isn't among the choices, the returned value is undefined.
- array_select_relative(current, delta, choices)
- Returns an array element in a position relative to a given value.
COPY/// @func array_select_relative(current, delta, choices)
///
/// @desc Returns an array element in a position relative to a given value.
/// If a relative position is beyond the range of given choices,
/// the position is clamped to be within range. If current value
/// isn't among the choices, the return value is undefined.
///
/// eg. select_relative("Name", -2, ["Hello", "Doctor", "Name"]) == "Hello"
/// select_relative("Doctor", 2, ["Hello", "Doctor", "Name"]) == "Name"
///
/// @param {any*} current value matching a given choice
/// @param {real} delta relative position of desired choice, integer
/// @param {array} choices array with a value to return, if selected
///
/// @return {any*} selected choice
///
/// GMLscripts.com/license
function array_select_relative(current, delta, choices)
{
var size = array_length(choices);
var list = ds_list_create();
var result = undefined;
for (var i = 0; i < size; i++) ds_list_add(list, choices[i]);
i = ds_list_find_index(list, current);
if (i >= 0) {
i = clamp(i + delta, 0, size - 1);
var result = ds_list_find_value(list, i);
}
ds_list_destroy(list);
return result;
}
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