'In a form' or 'of a form': how to express that something must conform to a given format?

Question

Which one is valid:

A date field should be in a form 'MM/DD/YYYY'.

or

A date field should be of a form 'MM/DD/YYYY'.

As in the question title, you probably want format rather than form.
If you use "format", I'd put it after the format you want: "in 'MM/DD/YYYY' format".
@coleopterist Apparently, OP did not want to use the technical term format for obvious reasons. Form is acceptable as an alternative when addressing a lay reader.

Kris · Accepted Answer · 2013-01-24 14:50:38Z

in the format is the general expression used in the context.

The definite article the will be needed.

A date field should be in the form 'MM/DD/YYYY'.

The alternate preposition of is acceptable in a similar way.

A date field should be of the form 'MM/DD/YYYY'.

1 Answer