Chinaunix

标题: 帮忙解释一下这段代码内部原理 $SEEK = "123.txt";open(SEEK); [打印本页]

作者: hitsubunnu 时间: 2008-03-10 18:39
标题: 帮忙解释一下这段代码内部原理 $SEEK = "123.txt";open(SEEK);
今天看到一段代码虽然知道运行结果但是不明白里面的原理

$SEEK = "123.txt";
open(SEEK);
while(<SEEK>){
print;
}
close SEEK;

复制代码

open(SEEK) 里面省略了什么？怎么把"123.txt"带进去的

作者: churchmice 时间: 2008-03-10 18:45
你确认是SEEK而不是$SEEK ??

作者: hitsubunnu 时间: 2008-03-10 18:46
不是你可以运行一下就是因为这个我才不理解呢

作者: churchmice 时间: 2008-03-10 18:49
果然神奇
see
perldoc -f open
open FILEHANDLE,EXPR
   open FILEHANDLE,MODE,EXPR
   open FILEHANDLE,MODE,EXPR,LIST
   open FILEHANDLE,MODE,REFERENCE
   open FILEHANDLE
            Opens the file whose filename is given by EXPR, and associates
            it with FILEHANDLE.

            (The following is a comprehensive reference to open(): for a
            gentler introduction you may consider perlopentut.)

            If FILEHANDLE is an undefined scalar variable (or array or hash
            element) the variable is assigned a reference to a new anony-
            mous filehandle, otherwise if FILEHANDLE is an expression, its
            value is used as the name of the real filehandle wanted.  (This
            is considered a symbolic reference, so "use strict 'refs'"
            should not be in effect.)

  If EXPR is omitted, the scalar variable of the same name as the
            FILEHANDLE contains the filename.  (Note that lexical vari-
            ables--those declared with "my"--will not work for this pur-
            pose; so if you're using "my", specify EXPR in your call to
            open.)

就是说open(FILEHANDLE)相当与