We are now ready to remove entries from rows that we know we don’t need. The entry header_index and everything before it should be removed. Entries for which n is 1 should also be removed, and the...

We are now ready to remove entries from rows that we know we don’t need. The entry header_index and everything before it should be removed. Entries for which n is 1 should also be removed, and the entry tail_index and everything that comes after it should be removed as well.

Now we are ready to remove all the non-numeric entries. Do this using regex and the str_remove_all function. Hint: remember that in regex, using the upper case version of a special character usually means the opposite. So \\D means “not a digit”. Remember you also want to keep spaces.