joining two variables and printing them to a file?

terms5 has asked for the wisdom of the Perl Monks concerning the following question:

In the code below I'm using the join function to make one variable that contains $timeHour, seperated by :, and $timeMinute. Then I'm reading from file fileTimes to fill the array @times with previously stored times. Then I'm putting(unshift)the joined variable I just made into the array of @times and printing the updated list back into fileTimes.
My question is this: Whenever I 'cat fileTimes' the output is always on two different lines like so:
12
:34
how do I make the file take it and display it like this:
12:34
I've tried it with strings and it works fine, but not with this. Thanks!

#!/usr/bin/perl -w

my @times;
my $timeDisplay;
my $timeMinute = `date '+%M'`;
my $timeHour = `date '+%H'`;

       $timeDisplay = join (":", "$timeHour", "$timeMinute");

        open(IN1, '<', 'fileTimes'); #fills @times with data in fileTi
+mes 
          while(my $line = <IN1>) {
                    chomp $line;
                    unshift(@times, $line);
                               }
        close(IN1);

unshift(@times, $timeDisplay); #puts in new time to queue

        open(FILE, ">fileTimes");
          foreach my $i (@times) { #prints back into fileTimes to upda
+te
                print FILE "$i\n";
                                 }
         close(FILE);
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Comment on joining two variables and printing them to a file? Download Code

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Re: joining two variables and printing them to a file? by GrandFather (Saint) on Apr 25, 2006 at 05:55 UTC
If I modifiy your code so that it is stand alone and doesn't require external applications then I don't see the problem you describe. Can you modify this code to reproduce the error (without introducing external dependencies)? `use strict; use warnings; my @times; my $timeDisplay; my $timeMinute = '56'; my $timeHour = '34'; while(my $line = <DATA>) { chomp $line; unshift(@times, $line); } $timeDisplay = join (":", "$timeHour", "$timeMinute"); unshift(@times, $timeDisplay); #puts in new time to queue foreach my $i (@times) { #prints back into fileTimes to update print "$i\n"; } __DATA__ 12:34 56:78` [download] Prints: `34:56 56:78 12:34` [download] My guess is that your external application (date) is returning newlines at the end of its string. You might want to take a look at some of the Perl date and time handling functions (time, gmtime and localtime) and modules (Date::EzDate and many others) rather than calling an external application. DWIM is Perl's answer to Gödel	[reply] [d/l] [select]
Re^2: joining two variables and printing them to a file? by terms5 (Initiate) on Apr 25, 2006 at 06:33 UTC
doh! It was date that was messing me up, the POSIX thing cleared it right up! Thanks a lot! I didn't even know those functions existed, guess I have a lot of reading to do. ^_^	[reply]
Re: joining two variables and printing them to a file? by Zaxo (Archbishop) on Apr 25, 2006 at 05:49 UTC
In line 21 you explicitly print a newline after each array element. You will get better use out of POSIX::strftime and perl's builtin localtime. Shelling out twice to system `date` to get the time in completely unnecessary. $ perl -MPOSIX=strftime -e'print strftime "%H:%M\n", localtime' 01:47 $ [download] POSIX::strftime() is like sprintf specialized for time structures. After Compline, Zaxo	[reply] [d/l]