Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
As part of my job, I review code by people that are less then experienced with Perl. I've seen some bad code such as:
open(F, "grep 'WARNING<\/font>' $mydir/$myfile".".|wc|awk '{print \$1} +'| ") ; while (<F>) { chomp(); $received_warn=$_; } close F;

Which is part of a larger script where the same file was opened and closed several times and processed as shown by scanning the entire file, looking for specific html, then counting rows in the output file for the condition. Meanwhile, all of the information needed for all of the processing was available from a single pass of the file head.

However, I think the most common mistake people make is confusing numeric comparisons with string comparisons. This kind of mistake often passes simple manual tests but breaks if it gets to production.

Example:
$a = 'a'; if ($a == 'b' or $a == 'c') { print "True\n"; }
...or even worse:
if ($a = 'b') { print "True\n"; }
Both examples print 'True', but the last example has corrupted your data.

In reply to Re: Little annoying mistakes ... of others by tprocter
in thread Little annoying mistakes ... of others by szabgab

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others rifling through the Monastery: (6)
As of 2024-03-28 08:12 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found