IT without boundaries So say the coffee mugs where I'm training this week - a company motto that seems very appropriate when I'm teaching about
Perl's lists. Most languages allow you to define a whole series of values in a single variable (an array), but if you're writing in C or Java, you're probably used to having to define the number of elements, and the size of each element, ahead of time. Perl is different - with Perl lists you can simply refer to the list for the first time and it will be created, and you can save as many values as you like into it and the list will be extended as need be to handle your request.
I must be fair to C and Java, though. In C, you can use calloc, malloc and realloc to dynamically assign memory if you wish and Java's Vector and ArrayList classes also let you set up a dynamic container in a similar way in that language.
(written 2005-03-09, updated 2006-06-05)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
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[738] (Perl) Callbacks - what are they? - (2006-05-30)
[930] -> , >= and => in Perl - (2006-11-18)
[968] Perl - a list or a hash? - (2006-12-06)
[1334] Stable sorting - Tcl, Perl and others - (2007-09-06)
[1705] Environment variables in Perl / use Env - (2008-07-11)
[1826] Perl - Subs, Chop v Chomp, => v , - (2008-10-08)
[1856] A few of my favourite things - (2008-10-26)
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[2833] Fresh Perl Teaching Examples - part 2 of 3 - (2010-06-27)
[2836] Perl - the duplicate key problem explained, and solutions offered - (2010-06-28)
[2915] Looking up a value by key - associative arrays / Hashes / Dictionaries - (2010-08-11)
[2920] Sorting - naturally, or into a different order - (2010-08-14)
[3042] Least Common Ancestor - what is it, and a Least Common Ancestor algorithm implemented in Perl - (2010-11-11)
[3072] Finding elements common to many lists / arrays - (2010-11-26)
[3106] Buckets - (2010-12-26)
[3400] $ is atomic and % and @ are molecular - Perl - (2011-08-20)
[3451] Why would you want to use a Perl hash? - (2011-09-20)
[3662] Finding all the unique lines in a file, using Python or Perl - (2012-03-20)
P208 - Perl - Lists [28] Perl for breakfast - (2004-08-25)
[140] Comparison Chart for Perl programmers - list functions - (2004-12-04)
[230] Course sizes - beware of marketing statistics - (2005-02-27)
[355] Context in Perl - (2005-06-22)
[463] Splitting the difference - (2005-10-13)
[560] The fencepost problem - (2006-01-10)
[622] Queues and barrel rolls in Perl - (2006-02-24)
[762] Huge data files - what happened earlier? - (2006-06-15)
[773] Breaking bread - (2006-06-22)
[928] C++ and Perl - why did they do it THAT way? - (2006-11-16)
[1304] Last elements in a Perl or Python list - (2007-08-16)
[1316] Filtering and altering Perl lists with grep and map - (2007-08-23)
[1703] Perl ... adding to a list - end, middle, start - (2008-07-09)
[1828] Perl - map to process every member of a list (array) - (2008-10-09)
[1918] Perl Socket Programming Examples - (2008-12-02)
[2067] Perl - lists do so much more than arrays - (2009-03-05)
[2226] Revision / Summary of lists - Perl - (2009-06-10)
[2295] The dog is not in trouble - (2009-07-17)
[2484] Finding text and what surrounds it - contextual grep - (2009-10-30)
[2813] Iterating over a Perl list and changing all items - (2010-06-15)
[2996] Copying - duplicating data, or just adding a name? Perl and Python compared - (2010-10-12)
[3548] Dark mornings, dog update, and Python and Lua courses before Christmas - (2011-12-10)
[3669] Stepping through a list (or an array) in reverse order - (2012-03-23)
[3870] Writing more maintainable Perl - naming fields from your data records - (2012-09-25)
[3906] Taking the lead, not the dog, for a walk. - (2012-10-28)
[3939] Lots of ways of doing the same thing in Perl - list iteration - (2012-12-03)
[4609] Mapping an array / list without a loop - how to do it in Perl 6 - (2016-01-03)
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