KSH | `-n` option inside an if statement

Question

I was checking a korn shell script and I stumbled upon this:

if [[ -n `echo "This is an example." | grep -E "example"` ]]; then
  # Do something.
fi

Can someone tell me what the -n is doing?

Answer 1

Suggesting to check this article:

 [[ -n "string" ]] true if length of string is greater than zero

Similar to

if [[ `echo "This is an example." | grep -Ec "example"` -gt 0 ]]; then
  # Do something.
fi

Also better practice for if statements:

if [[ -n $(echo "This is an example." | grep -E "example") ]]; then
  # Do something.
fi