为什么php表达式会返回值？

Question

For example, echo and print output similarly but print returns 1. My book says this is useful for expressions.

I'm what scenarios should I expect to return values in my expressions? What use is it?

Answer 1

for example : if you are dealing with post method and something went wrong you can use print_r($_POST); to see if the values are stored correctly.. hope that will help