Usually, when we have to display a text and we do not have enough space to display the whole text, it can be truncated and this could be indicated by an ellipsis.
See for example this question: Truncating long text labels - Best Practices?
But what should I do when I have a table containing data and there are numbers which are too large to be displayed.
Of course this is a situation which should be avoided, e.g. we could scale the data and indicate this. But in a framework which can be used to display any kind of data this can not be completely avoided.
I had a look at Excel and instead of displaying an ellipsis or simply truncating the number, they indicate that a number is too large (or better too wide) to be displayed by replacing the number with hash signs:
Is this a best practice? Can you explain the reasoning behind this?