ROS noetic view_frames TypeError: cannot use a string pattern on a bytes-like object
ROS noetic + Ubuntu20.04报错：
mc@ubun:~$ rosrun tf view_frames
Listening to /tf for 5.0 seconds
Done Listening
b'dot - graphviz version 2.43.0 (0)\n'
Traceback (most recent call last):
File "/opt/ros/noetic/lib/tf/view_frames", line 119, in <module>
generate(dot_graph)
File "/opt/ros/noetic/lib/tf/view_frames", line 89, in generate
m = r.search(vstr)
TypeError: cannot use a string pattern on a bytes-like object
查了一下，search函数需要输入str类型数据，而vstr（有可能？）不是str类型，所以需要把
m = r.search(vstr)
改成，
m = r.search(str(vstr))
如下，
try:
vstr = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[1]
except OSError as ex:
print("Warning: Could not execute `dot -V`. Is graphviz installed?")
sys.exit(-1)
v = distutils.version.StrictVersion('2.16')
r = re.compile(".*version (\d+\.?\d*)")
print(vstr)
m = r.search(str(vstr)) 不过同样官方的说法如下，
将
m = r.search(vstr)
改为，
m=r.search(vstr.decode('utf-8'))
我试了一下，两种都能给出正确的结果。