How can I use a filter to show everything except cells containing specific words?

Question

I'm importing a Google Calendar (ics link in A2 that I'm importing with an IMPORTDATA function) and it has system dates related to 1970 that I obviously want to filter.

How can I specify to show me everything EXCEPT cells containing DTSTART:1970*

=FILTER(index(IMPORTDATA(A2),,1), index(IMPORTDATA(A2),,1)<>"DTSTART:19700308T020000", index(IMPORTDATA(A2),,1)<>"DTSTART:19700405T030000", index(IMPORTDATA(A2),,1)<>"DTSTART:19701004T020000", index(IMPORTDATA(A2),,1)<>"DTSTART:19701101T020000")

Answer 1

Try this:

=query( importdata(A2), "select Col1 where not Col1 contains 'DTSTART:1970' ", 0 )

See the query language help page.