prevent loop from executing if variable is set

Question

I want to to execute an if statement a variable is set. I'm using bash.

Can I just use this statement:

if  [[ "$user_lives_here" ]]; then

Or is it better to use something like:

if  [[ ! -z "$user_lives_here" ]]; then

Answer 1

You can use

if [[ -v user_lives_here ]]  ; then
    echo "variable is set"
else
    echo "variable is not set"
fi