Ubuntu 20.04学习ros的时候输入catkin_make报错。

Question

最近在学习ROS，自己写了一个海龟的小程序想跑一下，没想到在catkin_make的时候出现了这样的状况。这两天快被弄疯了。不是道是不是anaconda和ros冲突的原因，求一个解决方法。

wulanbo@wulanbo-Lenovo-Legion-Y7000:~$ cd ~/catkin_ws
wulanbo@wulanbo-Lenovo-Legion-Y7000:~/catkin_ws$ catkin_make
Base path: /home/wulanbo/catkin_ws
Source space: /home/wulanbo/catkin_ws/src
Build space: /home/wulanbo/catkin_ws/build
Devel space: /home/wulanbo/catkin_ws/devel
Install space: /home/wulanbo/catkin_ws/install
####
#### Running command: "cmake /home/wulanbo/catkin_ws/src -DCATKIN_DEVEL_PREFIX=/home/wulanbo/catkin_ws/devel -DCMAKE_INSTALL_PREFIX=/home/wulanbo/catkin_ws/install -G Unix Makefiles" in "/home/wulanbo/catkin_ws/build"
####
-- Using CATKIN_DEVEL_PREFIX: /home/wulanbo/catkin_ws/devel
-- Using CMAKE_PREFIX_PATH: /opt/ros/noetic
-- This workspace overlays: /opt/ros/noetic
-- Using PYTHON_EXECUTABLE: /home/wulanbo/anaconda3/bin/python3
-- Using Debian Python package layout
-- Could NOT find PY_em (missing: PY_EM) 
CMake Error at /opt/ros/noetic/share/catkin/cmake/empy.cmake:30 (message):
  Unable to find either executable 'empy' or Python module 'em'...  try
  installing the package 'python3-empy'
Call Stack (most recent call first):
  /opt/ros/noetic/share/catkin/cmake/all.cmake:164 (include)
  /opt/ros/noetic/share/catkin/cmake/catkinConfig.cmake:20 (include)
  CMakeLists.txt:59 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/wulanbo/catkin_ws/build/CMakeFiles/CMakeOutput.log".
Invoking "cmake" failed

Answer 1

Using PYTHON_EXECUTABLE: /home/wulanbo/anaconda3/bin/python3

你使用的是anaconda的Python环境，你用conda list 看看你有没有安装 empy，没有装的话就要在conda里面安装它，conda install -c conda-forge empy

还有个方法就是不用anaconda的Python环境，把.bashrc里面的 export PATH="/home/用户名/anaconda3/bin:$PATH" 注释掉，再source一下