我需要重置一个Perl哈希索引吗？ [英] Do I need to reset a Perl hash index?

问题描述

好的，这是一个N00b问题，但它让我很难过：

我有以下Perl代码：

 ％project_keys =（
 cd =>continuous_delivery，
 cm =>customer_management，
 dem =>需求，
 dis =>dis，
 do =>devops，
 sel =>selection，
 seo =>seo 
）; 
 
 printproj_code is $ proj_code\\\
; （$ key $ value = $ project_keys）{
 if（$ key == $ proj_code）{
 $ url =http：// projects /。$ project_keys {$}键 /二传手。 
最后; 
 
 
  

$ proj_code 总是以相同的（'dis'）传递，打印行显示。然而，每次运行这个时，我都会得到 project_keys {$ key} 的不同值。

什么（毫无疑问，显而易见）我做错了什么？我已经看到有关每个脆弱的评论 - 是这样吗？

如果你已经有了钥匙 '期待，检查它是否存在并使用它...

另外，总是使用 use strict;使用警告;

 ＃！/ usr / bin / perl 
 
严格使用; 
使用警告; 
 
 my $ proj_code ='dis'; 
 my $ url; 
 $ b $ my％project_keys =（
 cd =>continuous_delivery，
 cm =>customer_management，
 dem =>demand，
 dis =>dis，
 do =>devops，
 sel =>selection，
 seo =>seo
 ）; 
 
 $ url =http：// projects / $ project_keys {$ proj_code} / setter
 if $ exists $ project_keys {$ proj_code}; 
 
打印url：$ url \\\
; b 
 
 
 
 $ b 
输出： code> url：http：// projects / dis / setter 
  

OK, this is a N00b question, but it's gotten me stumped:

I have the following Perl code:

%project_keys = (
  cd     => "continuous_delivery",
  cm     => "customer_management",
  dem    => "demand",
  dis    => "dis",
  do     => "devops",
  sel    => "selection",
  seo    => "seo"
);

print "proj_code is $proj_code\n";
while ( ($key, $value) = each %project_keys ) {
    if ($key == $proj_code) {
        $url = "http://projects/".$project_keys{$key}."/setter";
        last;
    }
}

$proj_code is always passed in the same ('dis') and the print line shows that.

However, each time I run this, I'm getting a different value for project_keys{$key}.

What (no doubt obvious) thing am I doing wrong? I have seen comments about how each is 'fragile' - is that it?

解决方案

If you already have the "key" you're expecting, check if it exists and use it...

Also, always use use strict; use warnings;

#!/usr/bin/perl

use strict;
use warnings;

my $proj_code= 'dis';
my $url;

my %project_keys = (
  cd     => "continuous_delivery",
  cm     => "customer_management",
  dem    => "demand",
  dis    => "dis",
  do     => "devops",
  sel    => "selection",
  seo    => "seo"
);

$url = "http://projects/$project_keys{$proj_code}/setter" 
    if exists $project_keys{$proj_code};

print "url: $url\n";

OUTPUTS:

url: http://projects/dis/setter

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