From the Perldoc page on [sleep][1]:

&gt; For delays of finer granularity than one second, the [Time::HiRes][2] module (from CPAN, and starting from Perl 5.8 part of the standard distribution) provides usleep().

Actually, it provides `usleep()` (which sleeps in microseconds) and `nanosleep()` (which sleeps in nanoseconds). You may want `usleep()`, which should let you deal with easier numbers. 1 millisecond sleep (using each):

    use strict;
    use warnings;

    use Time::HiRes qw(usleep nanosleep);

    # 1 millisecond == 1000 microseconds
    usleep(1000);
    # 1 microsecond == 1000 nanoseconds
    nanosleep(1000000);

If you don&#39;t want to (or can&#39;t) load a module to do this, you may also be able to use the built-in &lt;a href=&quot;http://perldoc.perl.org/functions/select.html&quot;&gt;`select()`&lt;/a&gt; function:

    # Sleep for 250 milliseconds
    select(undef, undef, undef, 0.25);

  [1]: http://perldoc.perl.org/functions/sleep.html
  [2]: http://perldoc.perl.org/Time/HiRes.html

Time::HiRes:

      use Time::HiRes;
      Time::HiRes::sleep(0.1); #.1 seconds
      Time::HiRes::usleep(1); # 1 microsecond.

http://perldoc.perl.org/Time/HiRes.html

From [perlfaq8](http://faq.perl.org/perlfaq8.html#How_can_I_sleep_or_a):

&lt;hr&gt;

**How can I sleep() or alarm() for under a second?**

If you want finer granularity than the 1 second that the sleep() function provides, the easiest way is to use the select() function as documented in select in perlfunc. Try the Time::HiRes and the BSD::Itimer modules (available from CPAN, and starting from Perl 5.8 Time::HiRes is part of the standard distribution).


Use [Time::HiRes][1].

[1]: http://perldoc.perl.org/Time/HiRes.html

A quick googling on &quot;perl high resolution timers&quot; gave a reference to [Time::HiRes][1]. Maybe that it what you want.

  [1]: http://search.cpan.org/dist/Time-HiRes/HiRes.pm

    system &quot;sleep 0.1&quot;;

does the trick.

This may seem stupid, but I still couldn&#39;t figure out how to mark a attribute as a primary key in the xcdatamodel file.
My persistent storage is sqlite file.
Can anyone help me?

In that case, how can I &quot;validate&quot; a ID to be unique?
Should I write a validation method or something?



Core Data Primary Key

I have two files, `node.py` and `path.py`, which define two classes, `Node` and `Path`, respectively.

Up to today, the definition for `Path` referenced the `Node` object, and therefore I had done

    from node.py import *

in the `path.py` file.

However, as of today I created a new method for `Node` that references the `Path` object.

I had problems when trying to import `path.py`: I tried it, and when the program ran and called the `Path` method that uses `Node`, an exception rose about `Node` not being defined.

What do I do?

Circular dependency in Python

How do I sleep for shorter than a second in Perl?

How do I sleep for a millisecond in Perl?

<p>How do I sleep for shorter than a second in Perl?</p>


How do I tell CPAN to install all dependencies?

I tried setting these in `cpan`:

    cpan&gt; o conf prerequisites_policy follow
    cpan&gt; o conf commit

I still had to answer &quot;y&quot; a couple of times (but fewer than before it feels like).

Is there a way to get it to always go ahead and install? I want to make it unattended. 

It would seem that I want a flag to always trust CPAN to do the right thing, and if it suggests an answer I would like to follow it (always hit &lt;kbd&gt;Enter&lt;/kbd&gt; when it asks something).


How do I tell CPAN to install all dependencies?

I&#39;m trying to open an .html file as one big long string.  This is what I&#39;ve got:

    open(FILE, &#39;index.html&#39;) or die &quot;Can&#39;t read file &#39;filename&#39; [$!]\n&quot;;  
    $document = &lt;FILE&gt;; 
    close (FILE);  
    print $document;

which results in: 

    &lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.01 Transitional//EN

However, I want the result to look like: 

    &lt;!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.01 Transitional//EN&quot; &quot;http://www.w3.org/TR/html4/loose.dtd&quot;&gt;
    &lt;html&gt;
    &lt;head&gt;
    &lt;meta http-equiv=&quot;Content-Type&quot; content=&quot;text/html; charset=iso-8859-1&quot;&gt;

This way I can search the entire document more easily.


In Perl, how can I read an entire file into a string?

One of my colleagues recently interviewed some candidates for a job and one said they had very good Perl experience.

Since my colleague didn&#39;t know Perl, he asked me for a critique of some code written (off-site) by that potential hire, so I had a look and told him my concerns (the main one was that it originally had no comments and it&#39;s not like we gave them enough time).

However, the code works so I&#39;m loathe to say no-go without some more input. Another concern is that this code basically looks exactly how I&#39;d code it in C. It&#39;s been a while since I did Perl (and I didn&#39;t do a lot, I&#39;m more a Python bod for quick scripts) but I seem to recall that it was a much more expressive language than what this guy used.

I&#39;m looking for input from real Perl coders, and suggestions for how it could be improved (and why a Perl coder *should* know that method of improvement).

You can also wax lyrical about whether people who write one language in a totally different language should (or shouldn&#39;t be hired). I&#39;m interested in your arguments but this question is primarily for a critique of the code.

The spec was to successfully process a CSV file as follows and output the individual fields:

    User ID,Name , Level,Numeric ID
    pax, Pax Morgan ,admin,0
    gt,&quot;  Turner, George&quot; rubbish,user,1
    ms,&quot;Mark \&quot;X-Men\&quot; Spencer&quot;,&quot;guest user&quot;,2
    ab,, &quot;user&quot;,&quot;3&quot;

The output was to be something like this (the potential hire&#39;s code actually output this):

    User ID,Name , Level,Numeric ID:
       [User ID]
       [Name]
       [Level]
       [Numeric ID]
    pax, Pax Morgan ,admin,0:
       [pax]
       [Pax Morgan]
       [admin]
       [0]
    gt,&quot;  Turner, George  &quot; rubbish,user,1:
       [gt]
       [  Turner, George  ]
       [user]
       [1]
    ms,&quot;Mark \&quot;X-Men\&quot; Spencer&quot;,&quot;guest user&quot;,2:
       [ms]
       [Mark &quot;X-Men&quot; Spencer]
       [guest user]
       [2]
    ab,, &quot;user&quot;,&quot;3&quot;:
       [ab]
       []
       [user]
       [3]

Here is the code they submitted:

    #!/usr/bin/perl

    # Open file.

    open (IN, &quot;qq.in&quot;) || die &quot;Cannot open qq.in&quot;;

    # Process every line.

    while (&lt;IN&gt;) {
        chomp;
        $line = $_;
        print &quot;$line:\n&quot;;

        # Process every field in line.

        while ($line ne &quot;&quot;) {
            # Skip spaces and start with empty field.

            if (substr ($line,0,1) eq &quot; &quot;) {
                $line = substr ($line,1);
                next;
            }

            $field = &quot;&quot;;
            $minlen = 0;

            # Detect quoted field or otherwise.

            if (substr ($line,0,1) eq &quot;\&quot;&quot;) {
                $line = substr ($line,1);
                $pastquote = 0;
                while ($line ne &quot;&quot;) {
                    # Special handling for quotes (\\ and \&quot;).

                    if (length ($line) &gt;= 2) {
                        if (substr ($line,0,2) eq &quot;\\\&quot;&quot;) {
                            $field = $field . &quot;\&quot;&quot;;
                            $line = substr ($line,2);
                            next;
                        }
                        if (substr ($line,0,2) eq &quot;\\\\&quot;) {
                            $field = $field . &quot;\\&quot;;
                            $line = substr ($line,2);
                            next;
                        }
                    }

                    # Detect closing quote.

                    if (($pastquote == 0) &amp;&amp; (substr ($line,0,1) eq &quot;\&quot;&quot;)) {
                        $pastquote = 1;
                        $line = substr ($line,1);
                        $minlen = length ($field);
                        next;
                    }

                    # Only worry about comma if past closing quote.

                    if (($pastquote == 1) &amp;&amp; (substr ($line,0,1) eq &quot;,&quot;)) {
                        $line = substr ($line,1);
                        last;
                    }
                    $field = $field . substr ($line,0,1);
                    $line = substr ($line,1);
                }
            } else {
                while ($line ne &quot;&quot;) {
                    if (substr ($line,0,1) eq &quot;,&quot;) {
                        $line = substr ($line,1);
                        last;
                    }
                    if ($pastquote == 0) {
                        $field = $field . substr ($line,0,1);
                    }
                    $line = substr ($line,1);
                }
            }

            # Strip trailing space.

            while ($field ne &quot;&quot;) {
                if (length ($field) == $minlen) {
                    last;
                }
                if (substr ($field,length ($field)-1,1) eq &quot; &quot;) {
                    $field = substr ($field,0, length ($field)-1);
                    next;
                }
                last;
            }

            print &quot;   [$field]\n&quot;;
        }
    }
    close (IN);


Should we hire someone who writes C in Perl?

If I have the following array in Perl:

    @x = qw(a b c);

and I iterate over it with `foreach`, then `$_` will refer to the current *element* in the array:

    foreach (@x) {
        print;
    }

will print:

    abc

Is there a similar way to get the *index* of the current element, without manually updating a counter? Something such as:

    foreach (@x) {
        print $index;
    }

where `$index` is updated like `$_` to yield the output:

    012



Automatically get loop index in foreach loop in Perl

I have a Perl script that is counting the number of occurrences of various strings in a text file. I want to be able to check if a certain string is not yet a key in the hash. Is there a better way of doing this altogether?

Here is what I am doing:

    foreach $line (@lines){
        if(($line =~ m|my regex|) )
        {
            $string = $1;
            if ($string is not a key in %strings) # &quot;strings&quot; is an associative array
            {
                $strings{$string} = 1;
            }
            else
            {
                $n = ($strings{$string});
                $strings{$string} = $n +1;
            }
        }
    }


How can I see if a Perl hash already has a certain key?

Is there a better way to engineer a `sleep` in JavaScript than the following `pausecomp` function ([taken from here][1])?

    function pausecomp(millis)
    {
        var date = new Date();
        var curDate = null;
        do { curDate = new Date(); }
        while(curDate-date &lt; millis);
    }


This is not a duplicate of https://stackoverflow.com/questions/758688/sleep-in-javascript-delay-between-actions; I want a *real sleep* in the middle of a function, and not a delay before a piece of code executes.


  [1]: http://www.sean.co.uk/a/webdesign/javascriptdelay.shtm

What is the JavaScript version of sleep()?

I&#39;ve seen a few solutions, including watch and simply running a looping (and sleeping) script in the background, but nothing has been ideal.

I have a script that needs to run every 15 seconds, and since cron won&#39;t support seconds, I&#39;m left to figuring out something else.

What&#39;s the most robust and efficient way to run a script every 15 seconds on unix? The script needs to also run after a reboot.

How to get a unix script to run every 15 seconds?

What is the difference between a `wait()` and `sleep()` in Threads?

Is my understanding that a `wait()`-ing Thread is still in running mode and uses CPU cycles but a `sleep()`-ing does not consume any CPU cycles correct?

Why do we have *both* `wait()` and `sleep()`: how does their implementation vary at a lower level?

Difference between wait() and sleep()

When does Java&#39;s Thread.sleep throw InterruptedException?  Is it safe to ignore it?  I am not doing any multithreading.  I just want to wait for a few seconds before retrying some operation.

When does Java&#39;s Thread.sleep throw InterruptedException?

I can give it floating point numbers, such as

    time.sleep(0.5)

but how accurate is it? If i give it

    time.sleep(0.05)

will it really sleep about 50 ms?

Content Type	Original Author	Original Content on Stackoverflow
Question	ˈoʊ sɪks	View Question on Stackoverflow
Solution 1 - Perl	Chris Lutz	View Answer on Stackoverflow
Solution 2 - Perl	Greg	View Answer on Stackoverflow
Solution 3 - Perl	brian d foy	View Answer on Stackoverflow
Solution 4 - Perl	TML	View Answer on Stackoverflow
Solution 5 - Perl	JesperE	View Answer on Stackoverflow
Solution 6 - Perl	Tim Tian	View Answer on Stackoverflow

How do I sleep for a millisecond in Perl?

Perl Problem Overview

Perl Solutions

Solution 1 - Perl

Solution 2 - Perl

Solution 3 - Perl

Solution 4 - Perl

Solution 5 - Perl

Solution 6 - Perl

Circular dependency in Python

Core Data Primary Key

Attributions