Asking about the efficiency of the PHP echo string output?

Want to know the following two forms of execution, which is more efficient, or have a higher method!!!
Output Form 1
echo ".... 2 ";
echo ".... 3 ";
echo ".... 4 ";
echo ".... 5 ";
echo ".... 6 ";
echo ".... 7 ";


Output Form 2
$str. = ".... 2 ";
$str. = ".... 3 ";
$str. = ".... 4 ";
$str. = ".... 5 ";
$str. = ".... 6 ";
$str. = ".... 7 ";
Echo $str;

Reply to discussion (solution)

Don't understand, oh oh

This is not much, see what you used to use.

Form 2 requires variable caching, not high natural efficiency
But at all times, efficiency obeys the task.

Refer here to calculate the time of execution
http://blog.csdn.net/php_boy/article/details/6450678

The first kind of course.
Str splicing, is more efficient and memory

OK
Echo ' ... a ', ' ... b ', ' ... c '//This way

1
High efficiency

