菜鸟求教，关于->和=>

ayybaby

刚刚接触perl
不了解-> 和=>，实在找不到合适的文档

请请教下各位大虾，这两个符号的作用、用法

Perl_Er

有一节专门讲操作符：http://perldoc.perl.org/perlop.html

The Arrow Operator

"-> " is an infix dereference operator, just as it is in C and C++. If the right side is either a [...] , {...} , or a (...) subscript, then the left side must be either a hard or symbolic reference to an array, a hash, or a subroutine respectively. (Or technically speaking, a location capable of holding a hard reference, if it's an array or hash reference being used for assignment.) See perlreftut and perlref.

Otherwise, the right side is a method name or a simple scalar variable containing either the method name or a subroutine reference, and the left side must be either an object (a blessed reference) or a class name (that is, a package name). See perlobj.



The =>  operator is a synonym for the comma except that it causes its left operand to be interpreted as a string if it begins with a letter or underscore and is composed only of letters, digits and underscores. This includes operands that might otherwise be interpreted as operators, constants, single number v-strings or function calls. If in doubt about this behaviour, the left operand can be quoted explicitly.

Otherwise, the => operator behaves exactly as the comma operator or list argument separator, according to context.

[ 本帖最后由 Perl_Er 于 2009-9-14 12:36 编辑 ]

ayybaby

Thanks

flw

先看小骆驼。
不系统地学，这方法就有问题。

dahe_1984

->我只知道用在数组，hash引用。


=>我知道用在定义hash对应关系时用的%hash = (                     
                     "DLT8000"     => "28",
                     "SuperDLT1"   => "41",
                     "SDLT320"     => "42",
                     "SONY-AIT2"   => "14",
                     "SONY-AIT3"   => "15",
                     "SONY-AIT4"   => "16",
                     )

shaneqi

原帖由 dahe_1984 于 2009-9-14 13:30 发表
->我只知道用在数组，hash引用。


=>我知道用在定义hash对应关系时用的%hash = (                     
                     "DLT8000"     => "28",
                     "SuperDLT1"   => "41",
    ...

->面向对象里面方法的调用也有.