在PHP中，echo后跟两个单引号是什么意思？

Question

I am going through someone else's code for a very old site and it has a lot of lines like this:

echo '';

I am not familiar with PHP, but having quickly gone through a syntax tutorial, it seems that this command would be printing the contents of the single quotes. However, the single quotes are empty, and there are LOTS of instances like these.

What is the purpose of having these lines, and how did they end up in the code?

Answer 1

You are right, they just print out empty string. I can only guess as to how they got into your code but it is surely safe to delete them.

Answer 2

Single or double quotes are used to denote strings, so with:

echo '';

You are printing empty string essentially nothing.

Answer 3

the only idea i can think of choosing '' vs "" is:

echo '"';    // print "
echo "'";    // print '