There are many Perl operators but here are a few of the most common ones:
Arithmetic Operators
+ addition  subtraction * multiplication / division

Numeric Comparison Operators
== equality != inequality < less than > greater than <= less than or equal >= greater than or equal

String Comparison Operators
eq equality ne inequality lt less than gt greater than le less than or equal ge greater than or equal

(Why do we have separate numeric and string comparisons? Because we don't have special variable types, and Perl needs to know whether to sort numerically (where 99 is less than 100) or alphabetically (where 100 comes before 99).
Boolean Logic Operators
(and
, or
and not
aren't just in the above table as descriptions of the operators  they're also supported as operators in their own right. They're more readable than the Cstyle operators, but have different precedence to &&
and friend.
Miscellaneous Operators
= assignment . string concatenation x string multiplication .. range operator (creates a list of numbers)

Many operators can be combined with a =
as follows:
$a += 1; # same as $a = $a + 1 $a = 1; # same as $a = $a  1 $a .= "n"; # same as $a = $a . "n";

Operator Precedence and Associativity
Perl operators have the following associativity and precedence, listed from highest precedence to lowest. Operators borrowed from C keep the same precedence relationship with each other, even where C's precedence is slightly screwy. (This makes learning Perl easier for C folks.) With very few exceptions, these all operate on scalar v
alues only, not array values.
left terms and list operators (leftward) left > nonassoc ++  right ** right ! ~ and unary + and  left =~ !~ left * / % x left +  . left << >> nonassoc named unary operators nonassoc < > <= >= lt gt le ge nonassoc == != <=> eq ne cmp left & left  ^ left && left  nonassoc .. ... right ?: right = += = *= etc. left , => nonassoc list operators (rightward) right not left and left or xor

No comments:
Post a Comment