Yes, You can do this by simply exporting your items and editing the spreadsheet and then loading it. However there are some things to know. The best thing to do is to edit one of your items in the dashboard first before you export it. That way you can see the difference.
To do this fine your item you want to start editing.
Let say you have Black shoe size 7 and Black shoe size 8, etc. (If you use a SKU or UPC you will need to delete the extra sizes first otherwise its going to say you already have that item.). So I would delete all the items except Black shoe size 7. In Black shoe size 7 I would:
Adjust the Name to Black Shoe - This will now be the name for all the variants.
Category, Description, Location, tax, should reflect accordingly. Now your variant probably says "Regular" that is the default. Change it to Size 7 or 7. The SKU and price and stock are the same.
Now click "Add Variation" Now put Size 8 or 8 and enter the SKU, Price and Stock for that size.
Repeat until you have all the sizes in for that item.
Then do it again, and again, and again.
As I mentioned you can now export your inventory and edit it in a spreadsheet. Using the one you just did you should be able to see the difference. I would do one and then try to upload it. You will then find your editing errors and learn from them. One thing I know is that the Description and Item name are the same for all Variations.
Hope that helps.
