Ubuntu 旋律未满足依赖

我正试图按照本页的说明在ubuntu 18.04上安装ros melodic， 当我使用此命令

sudo apt install ros-melodic-desktop-full

时，我收到以下消息

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 ros-melodic-desktop-full : Depends: ros-melodic-desktop but it is not going to be installed
                            Depends: ros-melodic-perception but it is not going to be installed
                            Depends: ros-melodic-simulators but it is not going to be installed
                            Depends: ros-melodic-urdf-sim-tutorial but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

我试图安装ros melodic desktop，但它一直给我错误消息。 请帮忙

sudo apt-get autoremove

---

如果这不起作用，那就重新安装ubuntu。这是一种更快地解决这些问题的方法。

您是否已经尝试过

sudo apt install-f

（就像那样）？如果这不能解决问题，那么检查apt来源，确保您仍然拥有ros回购协议。当然，运行一个

sudo-apt-update

，以确保包列表是最新的。请参阅：我尝试了所有这些，但仍然不起作用