Linux directory permissions meaning __linux

Linux "ls-al" displays directory permissions that differ from file permissions:
Drwxrwxrwx
-rwxrwxrwx
In this case, the row "D" on the directory is a directory, and the next line "-" is a file. In the permission representation of the directory, r is readable, meaning that the directory structure of the directory can be read, and can be understood to show the content when LL. W is writable, meaning that the files under the directory can be added to the check. X represents an executable, which means that the directory can be used as a working directory. What does the working directory mean? The way ☝️ can be understood is to be able to CD to such a directory.
For example:
1. The system has an account named Vbird, and the permissions of a directory are:
Drwxr–r–3 root root 4096 June 08:35. SSH
This vbird does not belong to the user group of this file, only has R permission, therefore cannot carry on the W x operation to this file, therefore, cannot switch to this directory.
2. One account name is Dmtsai, and his home folder has [rwx] permissions on/home/dmtsai,dmtsai for this directory. There is a file named The_root.data in this directory, which has the following permissions:
-rwx--1 root root ... the_root.data.
What is the Dmtsai permissions on this file. Can you delete this file?
First, the permissions for the other group in the The_root.data file are 0, and Dmtsai belongs to other for this file, so Dmtsai does not have any permissions on The_root.data.
Second, this file is in the Dmtsai directory, Dmtsai has [rwx] permissions on its directory, so it can be deleted.