# czech@xxxxxxxxx / 2015-10-14 23:32:40 -0700:
I probably should have clarified - the objective of the test is to see 
if
the environment variable is set or not. -z $ENV_VAR seems to return 1 
if
the environment variable is not set or is set to null (zero bytes).
zshexpn(1):
  ${+name}
      If name is the name of a set parameter `1' is substituted,
      otherwise `0' is substituted.
ps your first email is a reply to an email with a completely unrelated
topic.  don't do that.
  891     Oct 14 jagmeet bali    (  49) ZSH feature request if not 
present
  892     Oct 14 ZyX             (  53) |->
  893     Oct 14 Peter Stephenso ( 120) | `->
  894     Oct 14 czech@xxxxxxxxx (  60) `->Best Way to Test an
Environment Variable
  895     Oct 14 czech@xxxxxxxxx (  73)   `->