打印 常量 值

sunzhiguolu

1. #!/usr/bin/perl
   
2. use strict;
   
3. use warnings;
   
4. 
   
5. use constant Name = 'Tom';
   
6. printf ("%s\n", Name);

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print 函数, 常量值支持字符串内插吗? 谢谢大家.

只是一个红薯

Constants defined using this module cannot be interpolated into strings like variables. However, concatenation works just fine:

1.     print "Pi equals PI...\n";        # WRONG: does not expand "PI"
   
2.     print "Pi equals ".PI."...\n";    # right

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1.   use constant PI    => 4 * atan2(1, 1);
   
2.     use constant DEBUG => 0;
   
3.     print "Pi equals ", PI, "...\n" if DEBUG;
   
4.     use constant {
   
5.         SEC   => 0,
   
6.         MIN   => 1,
   
7.         HOUR  => 2,
   
8.         MDAY  => 3,
   
9.         MON   => 4,
   
10.         YEAR  => 5,
    
11.         WDAY  => 6,
    
12.         YDAY  => 7,
    
13.         ISDST => 8,
    
14.     };
    
15.     use constant WEEKDAYS => qw(
    
16.         Sunday Monday Tuesday Wednesday Thursday Friday Saturday
    
17.     );
    
18.     print "Today is ", (WEEKDAYS)[ (localtime)[WDAY] ], ".\n";

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http://perldoc.perl.org/constant.html

jason680

回复 1# sunzhiguolu

Would you like to use Readonly module ...

$ perl -e 'use Readonly; Readonly my $Name => "Tom"; print "name=$Name\n"'
name=Tom

   

sunzhiguolu

回复 2# 只是一个红薯
谢谢大神指点. 学习了.

   

sunzhiguolu

回复 3# jason680
这个好, 我就是这个意思. 多谢大神.

   

daili0703

sunzhiguolu

回复 6# daili0703
什么情况, 求解释.

   

daili0703

我是羡慕楼上的大神  好厉害   回复 6# daili0703