perl标示符概览
本文主要对学习perl过程进行记载,方便后期学习
#!/usr/bin/perl # This is a single line comment print "Hello,world\n"; =begin comment 注释块,以=开始, 以=cut结束 This is all part of multiline comment. You can use as many lines as you like These comments will be ignored by the compiler until the next =cut is encountered. =cut
1.双引号能解释当中引用的变量,单引号不会打印出变量值
2.\为escape特殊符号
3.perl标示符标示变量,方法名,类名,模块名和其他对象。perl标示符用$,@,%后接一个多多哥字符,下划线以及数字(0-9)
perl变量
perl为宽松类型语言,大致有三种类型1. 标量 $ 2. 数组@ 3 Hashes %
数字分为有符号整型态以及双精度浮点数,另外还有字符串,同时要注意字符串中的backslash的特殊字符,列表如下所示意
Escape sequence | Meaning |
---|---|
\\ | Backslash |
\' | Single quote |
\" | Double quote |
\a | Alert or bell |
\b | Backspace |
\f | Form Feed |
\n | Newline |
\r | Carriage return |
\t | Horizontal tab |
\v | Vertical tab |
\0nn | Creates Octal formatted numbers |
\xnn | Creates Hexideciamal formatted numbers |
\cX | Control characters,x may be any character |
\u | Force next character to uppercase |
\l | Force next character to lowercase |
\U | Force all following characters to uppercase |
\L | Force all following characters to lowercase |
\Q | Backslash all following non-alphanumeric characters |
\E | End \U,\L,or \Q |