How would you see ia a sentence had a comma splice?

A comma splice occurs when two independent clauses are joined by only a comma. If each of the two parts separated by the comma can stand on its own as a complete sentence, then you have a comma splice.

Example: I did not get any sleep before my early flight, I slept on the plane.
Each of the two parts can stand alone as a sentence: "I did not get any sleep before my early flight." "I slept on the plane."

When these two parts are joined by only a comma, the result is a comma splice.