Category: Tech

I’m not a Django programmer, but for those who are, this may be useful. YouTube has videos of the inagural DjangoCon conference:
[http://www.youtube.com/results?search_query=djangocon&search=tag](http://www.youtube.com/results?search_query=djangocon&search=tag)

The Pragmatic Bookshelf is releasing a [book on using Git](http://www.pragprog.com/titles/tsgit/pragmatic-version-control-using-git) for version control.

Steven Walter released a new command-line front-end for git called [yap](http://lwn.net/Articles/297285/). It’s not only supposed to make it easier to work with git, but also with subversion repositories. It’s available from [http://repo.or.cz/w/yap.git](http://repo.or.cz/w/yap.git)

I’ve often wondered why people seem to prefer either MySQL or PostgreSQL. For the most part, I think it comes down to the following:

* Familiarity.
* Friends (a.k.a. support system) being more familiar with one over the other.
* Ease of getting started. Most web hosting providers support MySQL out-of-the box.
* Name recognition.
* Ease of support.

Here are some resources that could be useful for learning the pros and cons of each database:

* [What MySQL can learn from PostgreSQL](http://www.scribd.com/doc/2575733/The-future-of-MySQL-The-Project)
* [What can PostgreSQL learn from MySQL](http://www.postgresonline.com/journal/index.php?/archives/48-What-can-PostgreSQL-learn-from-MySQL.html) and the [accompanying presentation](http://www.commandprompt.com/files/mysql_learn.pdf)
* [MySQL quirks and limitations](http://use.perl.org/~Smylers/journal/34246)
* [Why PostgreSQL?](http://wiki.postgresql.org/wiki/Why_PostgreSQL_Instead_of_MySQL:_Comparing_Reliability_and_Speed_in_2007)

I thought it’d be interesting to know what times of day people were most likely to send me email. My email is stored in mbox format (I used Thunderbird and mutt for email), so I wrote a perl one-liner to analyze it for me.

The first one-liner prints a histogram, in 80 columns, of activity per-hour of the day. The second prints it in a form suitable for import into a spreadsheet

Histogram:

perl -nle ‘$sum[$1]++ if m/^Date: .* (\d\d):\d\d:\d\d/; END {foreach (@sum) { $max = $_ if $_ > $max }; $div = $max/80; foreach (@sum) { print $i++ . ” ” . (“#” x ($_ / $div)) . ” ($_)”;}}’ /path/to/Inbox

0 #################################### (115)
1 ########################## (84)
2 ################### (62)
3 ################ (54)
4 ############ (40)
5 ######### (31)
6 ####### (23)
7 ######################## (79)
8 ####################################### (126)
9 ############################################### (152)
10 ######################################### (133)
11 ###################################### (124)
12 ############################################################### (202)
13 ############################################################## (200)
14 ############################################################ (192)
15 #################################################################### (218)
16 ######################################################################## (229)
17 ################################################################ (206)
18 ################################################## (160)
19 ############################### (101)
20 ##################################### (118)
21 ######################################## (129)
22 ######################################################### (183)
23 ######################################## (129)

Tabular data:

perl -nle ‘$sum[$1] += 1 if m/^Date: \w{3}, \d+ \w{3} \d{4} (\d\d):\d\d:\d\d/; END {foreach (@sum) { print $i++ . “\t” . $_;} }’ /path/to/Inbox

While I was at it, I wanted to know what the most common timezone offsets were. Again, I wrote two separate one-liners. One prints a histogram, and the other doesn’t.

Histogram:

perl -nle ‘$tz{$1} += 1 if m/^Date: .*([+-]\d{4})/; END {foreach (values %tz) {$max = $_ if $_ > $max }; $div = $max/80; foreach (sort(keys %tz)) { print “$_ ” . (“#” x ($tz{$_}/$div)) . ” ($tz{$_})”; }}’ /path/to/Inbox

Non-histogram:

perl -nle ‘$tz{$1} += 1 if m/^Date: .*([+-]\d{4})/; END {foreach (sort(keys %tz)) { print “$_ $tz{$_}”; }}’ /path/to/Inbox

I subscribe to various email lists, and each has different characteristics. I was surprised to find that my family email box usage pattern was fairly spread out around the clock, except that it drops off significantly during dinner and during the wee hours of the morning. Evening hours are the most active.

I’ve taken the timezone one-liner and modified it to tell me the most common months of the year, or the most common days of the week for email to be sent. For all my email boxes, analyzed over the last few years, email is most active on weekdays, and drops off on weekends.

Mon ############################################################### (5630)
Tue ##################################################################### (6129)
Wed ######################################################################## (6372)
Thu ##################################################################### (6155)
Fri ############################################################ (5329)
Sat ############################## (2675)
Sun ########################## (2368)

I tried translating those one-liners into Ruby, but it wasn’t as compact, and doing it as a one-liner in Java just isn’t going to happen.

Moritz Lenz has written a series of informative blog posts about Perl 6, for Perl 5 programmers. Here’s a bit of his introduction:

> Perl 6 is underdocumented. That’s no surprise, because (apart from the specification) writing a compiler for Perl 6 seems to be much more urgent than writing documentation that targets the user.

> Unfortunately that means that it’s not easy to learn Perl 6, and that you have to have a profound interest in Perl 6 to actually find the motivation to learn it from the specification, IRC channels or from the test suite.

> This project, which I’ll preliminary call “Perl 5 to 6” (in lack of a better name) attempts to fill that gap with a series of short articles.

[Read more…](http://perlgeek.de/blog-en/perl-5-to-6/)