Re: first perl example from perl book

This is a problem more easily seen than described. If you use conveninetstore's "read" modification (and changing DAT to DATA), you get this result:

C:\Code>perl averages.pl
kim: 50 Average: 50
lee: 75 Average: 75
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If you then revert to the original ".=" code, you get this result:

C:\Code>perl averages.pl
kim: 90 90 95 100 50    Average: 85
lee: 99 100 75  Average: 91.3333333333333
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Clearly, when you do a concatenation, you add data repeatedly to the hash. When you just assign, you get only the last data entry read.

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Re^2: first perl example from perl book by convenientstore (Pilgrim) on Jan 15, 2008 at 16:30 UTC
thank you guys, I see the difference now `$grades{$student} .= $grade . " "; ./perl.score $grades{lee} is 90 $grades{lee} is 90 100 $grades{kim} is 90 $grades{kim} is 90 90 kim: 90 90 Average: 90 lee: 90 100 Average: 95 $grades{$student} .= " " . $grade ; [root@myserver chaos]# ./perl.score $grades{lee} is 90 $grades{lee} is 90 100 $grades{kim} is 90 $grades{kim} is 90 90 kim: 90 90 Average: 90 lee: 90 100 Average: 95` [download]	[reply] [d/l]

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Re^2: first perl example from perl book
by convenientstore (Pilgrim) on Jan 15, 2008 at 16:30 UTC

$grades{$student} .= $grade . " ";
./perl.score
$grades{lee} is 90 
$grades{lee} is 90 100 
$grades{kim} is 90 
$grades{kim} is 90 90 
kim: 90 90      Average: 90
lee: 90 100     Average: 95




$grades{$student} .= " " . $grade ;
[root@myserver chaos]# ./perl.score
$grades{lee} is  90
$grades{lee} is  90 100
$grades{kim} is  90
$grades{kim} is  90 90
kim:  90 90     Average: 90
lee:  90 100    Average: 95
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