Dot operator in PHP

Question

I thought I've known the String Operator . well enough until I was asked a question about it today. The question looks quite simple:

echo 100...100;

At the first glance I thought it would make a syntax error. But when I ran the code and saw the result I was totally confused. The result is

1000.1

So I wonder how could this happen?

Thanks.

Answer 1

Read it like this:

(100.) . (.100)

Thus it concats 100 and 0.1.