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printf confusion

by dusk (Friar)
on Feb 21, 2001 at 07:17 UTC ( #59837=perlquestion: print w/replies, xml ) Need Help??

dusk has asked for the wisdom of the Perl Monks concerning the following question:

I am having a bit of trouble with a Napster client I am writing (using deprecated's MP3::Napster module)

The client included with MP3::Napster uses a similar sub to the one below to recieve a list of names in the channel:

109 sub names 110 { 111 unless ($nap_object->channel){ 112 print qq-No current channel\n-; 113 return; 114 } 115 foreach ($nap_object->users) { 116 printf "\t([ %-20s ]) (%-9s)(%4d)\n",$_,$_->s +haring,$_->link; 117 } 118 }
However, this returns: Argument "DSL" isn't numeric in printf at perl/duskster/ line 116. I was informed that printf is unecessary in perl, and that there are far better ways to do it. Any suggestions/fixes will be greatly appreciated :)

Replies are listed 'Best First'.
Re: printf confusion
by AgentM (Curate) on Feb 21, 2001 at 07:23 UTC
    If you don't want to use printf, then simply use print. The current printf will give you a nice tab and lined up stuff, but otherwise, if you don't know how to use it, you will simply get confused. The error has something to do with $nap_object->users->link- which is not a number. If this is a string (I'm not familiar with this module) and you wish to print it, then switch that last 'd' in your printf line to 's'. 'd' specifies a digit and that variable doesn't seem to be a number, hence the error.
    AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.
Re: printf confusion
by BlueLines (Hermit) on Feb 21, 2001 at 07:25 UTC
    This is fine. You just need to do sanity checking on $_->link, which (in theory) usually is a number (14.4, 28.8), but can also be a string (DSL, CABLE, Unknown). Change the %4d to %-6s for instance, and everything will work fine.


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