(1,2,3) # array of three values 1, 2, and 3 ("fred",4.5) # two values, "fred" and 4.5
($a, 17) # two values: the current value of $a, and 17 ($b+$c,$d+$e) # two values
() # the empty list (zero elements)
An item of the list literal can include the list constructor function, indicated by two scalar values separated by two consecutive periods. This function creates a list of values starting at the left scalar value and continuing up through the right scalar value, incrementing by one at each value. For example:
(1..5) # same as (1, 2, 3, 4, 5) (1.2..5.2) # same as (1.2, 2.2, 3.2, 4.2, 5.2) (2..6,10,12) # same as (2,3,4,5,6,10,12) ($a..$b) # range determined by current values of $a and $b
Having the right scalar less than the left scalar results in an empty list; you can't count down by switching the order of the values. If the final value is not a whole number of steps above the initial value, the list stops just before the next value would have been outside the range:
(1.3..6.1) # same as (1.3,2.3,3.3,4.3,5.3)
List literals with lots of short text strings start to look pretty noisy with all the quotes and commas:
@a = ("fred","barney","betty","wilma"); # ugh!
Fortunately, Perl has a shortcut: the "quote-word" syntax, which creates a list from the nonwhitespace parts between the parentheses:
@a = qw(fred barney betty wilma); # better! @a = qw( fred barney betty wilma ); # same thing
print("The answer is ",$a,"\n"); # three element literal array
This statement prints "
The answer is" followed by a space, the value of
$a, and a newline. Stay tuned for other uses for list literals.