What is the difference between echo and print?
Which is faster, echo or print?

1. Speed. There is a difference between the two, but speed-wise it
should be irrelevant which one you use. echo is marginally faster
since
it doesn't set a return value if you really want to get down to the
nitty gritty.

2. Expression. print() behaves like a function in that you can do:
$ret = print "Hello World"; And $ret will be 1. That means that print
can be used as part of a more complex expression where echo cannot. An
example from the PHP Manual:

   $b ? print "true" : print "false";

print is also part of the precedence table which it needs to be if it
is
to be used within a complex expression. It is just about at the bottom
of the precedence list though. Only "," AND, OR and XOR are lower.

3. Parameter(s). The grammar is: echo expression [, expression[,
expression] ... ] But echo ( expression, expression ) is not valid.
This would be valid: echo ("howdy"),("partner"); the same as: echo
"howdy","partner";   (Putting the brackets in that simple example
serves
no purpose since there is no operator precedence issue with a single
term like that.)

So, echo without parentheses can take multiple parameters, which get
concatenated:

   echo "and a ", 1, 2, 3;   // comma-separated without parentheses
   echo ("and a 123");        // just one parameter with parentheses

print() can only take one parameter:

   print ("and a 123");
   print "and a 123";

source: http://www.forumnettr.com
http://www.forumnettr.com/forum

转自 http://www.faqts.com/knowledge_base/view.phtml/aid/1/fid/40