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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Perl - skip the classics and use regular expressions

Perl includes a number of "classic" string handling functions - things like index to find one string in another and substr to get a substring. But you very rarely need to use them because the other string handling functions that are provided are so much more powerful!

Here's an example - firstly showing the Perl way to replace one string with another, then the "classic" method that might be used by someone who's familiar with C and perhaps hasn't been on our Perl Course.

print "Where are you? ";
chop($place = <STDIN>);
 
$showem = "It is nice to be in HERE in June\n";
$showem =~ s/HERE/$place/;
print $showem;
 
$showem = "It is nice to be in HERE in June\n";
$pol = index($showem,"HERE");
$part1 = substr($showem,0,$pol);
$part2 = substr($showem,$pol+4);
$showem = $part1 . $place . $part2;
print $showem;


So that's 4 lines replaced by one and they have exactly the same effect:

Dorothy-2:de grahamellis$ perl altern
Where are you? Nuremberg
It is nice to be in Nuremberg in June
It is nice to be in Nuremberg in June
Dorothy-2:de grahamellis$


Oh - I tested the data using "Nuremberg" as my input, as that's where I am training this week. And it is nice in Nuremberg, although I would love to have had someone here to share it with me ;-).


(written 2010-06-08)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P205 - Perl - Initial String Handling
  [31] Here documents - (2004-08-28)
  [254] x operator in Perl - (2005-03-22)
  [324] The backtick operator in Python and Perl - (2005-05-25)
  [970] String duplication - x in Perl, * in Python and Ruby - (2006-12-07)
  [987] Ruby v Perl - interpollating variables - (2006-12-15)
  [1195] Regular Express Primer - (2007-05-20)
  [1608] Underlining in Perl and Python - the x and * operator in use - (2008-04-12)
  [1849] String matching in Perl with Regular Expressions - (2008-10-20)
  [1860] Seven new intermediate Perl examples - (2008-10-30)
  [2816] Intelligent Matching in Perl - (2010-06-18)
  [2832] Are you learning Perl? Some more examples for you! - (2010-06-27)
  [2963] Removing the new line with chop or chomp in Perl - what is the difference? - (2010-09-21)
  [3005] Lots of ways of doing it in Perl - printing out answers - (2010-10-19)
  [3411] Single and double quotes strings in Perl - what is the difference? - (2011-08-30)
  [3547] Using Perl to generate multiple reports from a HUGE file, efficiently - (2011-12-09)
  [3548] Dark mornings, dog update, and Python and Lua courses before Christmas - (2011-12-10)
  [3770] Sample answers to training course exercises - available on our web site - (2012-06-21)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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