Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

Re: while(<>) { ... } considered harmful

by dws (Chancellor)
on Sep 07, 2002 at 23:37 UTC ( #195930=note: print w/ replies, xml ) Need Help??


in reply to while(<>) { ... } considered harmful

Since   map { substr($_, 1, 1) = "foo" } qw(bar baz);
and   grep { substr($_, 1, 1) = "foo" } qw(bar baz);
both exhibit the problem you've observed, perhaps the advice might better be phrased

Don't write to $_ from within map { } or grep { }

local $_; is one way to avoid writing to it, since the 'it' is now different.


Update: Hm.. It's a bit worse than that.   foreach ( qw(foo) ) { $_ = 1 }
also exhibits the problem.


Comment on Re: while(<>) { ... } considered harmful
Select or Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://195930]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others avoiding work at the Monastery: (4)
As of 2014-09-21 17:39 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    How do you remember the number of days in each month?











    Results (173 votes), past polls