We still haven't finished learning from that humble bit of code. To refresh your memory, here it is again:
$string="perl"; $num1=20; $num2=10.75; print "The string is $string, number 1 is $num1 and number 2 is $num2\n";
Notice the way the variables are used in the string. Sticking
variables inside of strings has a technical term - "variable
interpolation". Now, if we didn't have the handy
$ prefix for we'd have to do something like
the example below, which is pseudocode. Pseudocode is code to
demonstrate a concept, not designed to be run. Like certain Microsoft
print "The string is ".string." and the
number is ".num."\n";
which is much more work. Convinced about those prefixes yet ?
Try running the following code:
$string="perl"; $num=20; print "Doubles: The string is $string and the number is $num\n"; print 'Singles: The string is $string and the number is $num\n';
Double quotes allow the aforementioned variable interpolation. Single quotes do not. Both have their uses as you will see later, depending on whether you wish to interpolate anything.