Here's how I understand the problem:
You have an import file that contains a set of records. The set includes some records that you want to keep and some you don't want to keep.
You know in advance the identiites of the records you don't want to keep.
Example you have records for rooms 1-100 but don't want to keep rooms 19, 23, 88.
If I were doing this I would import the WHOLE file. This is very fast. Then I would delete the records I don't want. This also is very fast. ("DELETE FROM myTable WHERE roomnumber IN (19,23,88)").
Beats having to do
csv>array>fix the array> csv>file>import fixed csv