这个问题可能与ROS完全有关，但是，目前我不确定错误的来源。因此，我将其发布在这个大社区中。
我正在尝试在 Ubuntu 18.04.2 LTS PC 上安装ROS Melodic。不幸的是，命令sudo apt install ros-melodic-desktop-full失败了。下面是相同命令的输出，再次运行时：
ravi@lab:~$ sudo apt install ros-melodic-desktop-full
Reading package lists... Done
Building dependency tree
Reading state information... Done
ros-melodic-desktop-full is already the newest version (1.4.1-0bionic.20190204.220757).
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
python-rosdistro-modules : Depends: python-rospkg-modules but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a …