setting indices to true or false

["Leeds, Mark" <mleeds@mlp.com>]

I have a vector of trues and falses

Called longentryindex and I want to set some of them

myself but I can’t find the syntax

In any book and I have three of them.

 

Would it be Longentryindex[3]_F

 

Or

 

Longentryindex[3]_FALSE

 

 

Or  something like

 

Longentryindex[3]_(1 == 0 )