Table headers style: repetition

Question

If I have a table w/ a header:

-----------------------------------------------------------------------
| IPv4 addresses wanted | IPv4 addresses used | IPv4 addresses wasted |
-----------------------------------------------------------------------
| 100                   | 80                  | 20                    |
-----------------------------------------------------------------------

& if I want to reduce the "repetitiveness" of the headers, which symbol(s) should I use as a placeholder for "IPv4 addresses" sub-string? I vaguely remember that in school I've used "-/-" string in similar cases, but I'm not really sure that it's not a false memory.

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| IPv4 addresses wanted | -/- used | -/- wasted |
-------------------------------------------------
| 100                   | 80       | 20         |
-------------------------------------------------

Answer 1

In this case you're saving exactly one character ("IPv4" vs "-/-") which isn't worth the extra effort that your users need to expend in order to figure out what you meant.

Also this symbol of repetition/substitution is highly localized and I wouldn't expect too many users to be familiar with it.

A better way to handle it would be to take the repeating element outside of the table and style it as a title. It also makes sense because this seems to be the entity around which the table revolves. In addition, it lets you reduce the width of the columns and make them as wide as needed for the numbers (the discrepancy between the width of the title and the width of the content can be a frequent problem in tables containing numbers).

IPv4 addresses
-------------------------------------------------
| Wanted | Used | Wasted |
-------------------------------------------------
| 100    | 80   | 20     |
-------------------------------------------------

Answer 2

If you give this table a title called "IP4 Addresses" and now your column headings can just be:

• Wanted
• Used
• Wasted

This is a different way to remove the repetition.