A Brief discussion on the problem of os.path.join slash in python splicing path

During debugging, a backslash was found on the path spliced through os.path.join

directory1='/opt/apps/upgradePackage'
directory2='icp_v1.8.0'
directory3=os.path.join(directory1,directory2)
print('directory3 : %s' %directory3)

The execution result

directory3 : /opt/apps/upgradePackage\icp_v1.8.0

Splicing symbol became "\", research along while, the discovery is the first directory behind the missing "/", plus "/", the program execution is correct.

directory1='/opt/apps/upgradePackage/'

The execution result

directory3 : /opt/apps/upgradePackage/icp_v1.8.0