Fastest way to look at first row of massive matrix table

Hail Query & hailctl
1

I turned a massive VDS file into a matrix table. What is the fastest way to look at a single entry in a row or field?

2

Do you just want it as a Python array? If you want a particular field you can do this:

mt.head(1).GT.collect()

If you want all the entry fields:

mt.head(1).entry.collect()

The row fields:

mt.head(1).row.collect()

If you want to get the row fields and the entry fields in one execution, you have to use this rather poorly named method (mea culpa for the name):

mt.head(1).localize_entries('entries').collect()

localize_entries converts from a MatrixTable to a Table by converting the entries into an array in the row table and returning just the row table.