给出以下地图列表:
ball_prop_list =
[
%{"id" => "cue", "is_idle" => true, "velocity_x" => 0.0, "velocity_z" => 0.0, "x" => -15.0, "z" => 0.0},
%{"id" => "ball_1", "is_idle" => true, "velocity_x" => 0.0, "velocity_z" => 0.0, "x" => 15.0, "z" => 0.0},
%{"id" => "ball_2", "is_idle" => true, "velocity_x" => 0.0, "velocity_z" => 0.0, "x" => 17.0, "z" => 1.1},
%{"id" => "ball_3", "is_idle" => true, "velocity_x" => 0.0, "velocity_z" => 0.0, "x" => 17.0, "z" => -1.1}
]
我该如何改变,比如说,只是velocity_x
and velocity_y
of "id" => "cue"
,并保持其他一切不变?
我只尝试使用更新的值创建一个新列表(这不一定是我的目标),如下所示:
new_prop_list = Enum.map(balls_json_list, fn(val) ->
if val["id"] == "cue" do
Map.put(val, "velocity_x" velocity_vector[:x])
Map.put(val, "velocity_z" velocity_vector[:z])
end
end)
但这并没有成功,可能是因为我的地图不使用原子键 - 到目前为止我看到的所有其他示例都使用原子键,或者添加新的键和值等。
还有什么我可以尝试的吗?