If the structure of the dataset is consistent (the cell contains either a string or number followed by space/dash/space) you could first expand the values, then use IF formula to gather the text values in one field.
Another useful tip:
If you want to see if the first character of a string is a text or a number, you can use the following function in a formula field:

TYPEOF(value(left([my_string], 1)))

This returns the type of the argument passed to it (e.g. text, decimal, integer)