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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Perl - a quick reminder and revision. Test yourself!

At the start of the second day of my second Perl course this week (yes, really!!) I put up a quick revision of what I had covered on the first day for my not - really - new - to - Perl group. How many of these things are you familiar with?

Comments ...

Don't forget to comment your code!
- # to end of line
- after __END__ on the end of the file
- "Documentation comments" via POD ... =head (etc) to =cut

Variables ...

$ - scalar. Integer, Float, String ... Reference, Regex
@ - list. Indexed ordered collection of scalars []
% - hash. Keyed unordered collection of scalars {}
& - code. a.k.a. a "sub"
  - file handle [no special start character)
* - typeglob - one of each of the above

Strings ...

" and ' (operator and literal). operator expanding $ @ \
Also qq and q, and "here documents"

Testing ...

== numeric equality !=
eq string equality ne
=~ string match !~

Regular Expressions contain ...

- literals. A 3 @ \+ \.
- char groups [A-Z] [^aeiou] . \s \d \w \W \D \S
- counts * ? + {2,6}
- anchors ^ $ \b
- captures ()
- alternation |
/.../ m!...! m/.../

Special Variables...

$& - the bit that matched
@_ - parameters to a sub
$1 - first interesting bit ...
@ARGV - incoming parameters to program
%ENV - environment variables
@INC - where modules may load from
%INC - where modules have been loaded from
$_ - default input and pattern matching space

Conditionals ...

if, unless, and, or, &&, ||, ? ... :

Loops ...

while, for, foreach, goto (yuk!), do while, until
last, next, redo

On a public Perl course, I would expect to take much longer than just one day to cover this little lot!


(written 2011-08-26)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P251 - Perl Review
  [2242] So what is this thing called Perl that I keep harping on about? - (2009-06-15)
  [3007] Setting up a matrix of data (2D array) for processing in your program - (2010-10-21)
  [3042] Least Common Ancestor - what is it, and a Least Common Ancestor algorithm implemented in Perl - (2010-11-11)
  [3430] Sigils - the characters on the start of variable names in Perl, Ruby and Fortran - (2011-09-10)

P050 - Perl - General
  [116] The next generation of programmer - (2004-11-13)
  [400] New in the shops - (2005-08-01)
  [743] How to debug a Perl program - (2006-06-04)
  [1750] Glorious (?) 12th August - what a Pe(a)rl! - (2008-08-12)
  [1897] Keeping on an even keel - (2008-11-21)
  [2228] Where do I start when writing a program? - (2009-06-11)
  [2374] Lead characters on Perl variable names - (2009-08-24)
  [2504] Learning to program in ... - (2009-11-15)
  [2736] Perl Course FAQ - (2010-04-23)
  [2783] The Perl Survey - (2010-05-27)
  [2825] Perl course - is it tailored to Linux, or Microsoft Windows? - (2010-06-25)
  [2971] Should the public sector compete with businesses? and other deep questions - (2010-09-26)
  [3093] How many toilet rolls - hotel inventory and useage - (2010-12-18)
  [3322] How much has Perl (and other languages) changed? - (2011-06-10)
  [3332] DNA to Amino Acid - a sample Perl script - (2011-06-24)
  [3823] Know Python or PHP? Want to learn Perl too? - (2012-07-31)
  [3902] Shell - Grep - Sed - Awk - Perl - Python - which to use when? - (2012-10-22)
  [3911] How well do you know Perl and / or Python? - (2012-11-04)
  [4296] Polishing the Perl courses - updated training - (2014-09-17)
  [4301] Perl - still a very effective language indeed for extracting and reporting - (2014-09-20)


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Not multidimentional arrays - but lists of lists. Much more flexible. Perl!
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When variables behave differently - Tie in Perl
Journey home by public transport for a Bank Holiday
Perl - a quick reminder and revision. Test yourself!
Not multidimentional arrays - but lists of lists. Much more flexible. Perl!
Where do businessmen stay in Melksham?
Buses on the Cambridge Guided Busway
Last chance this summer - Swindon and North Wiltshire to Weymouth by through train
That spec is a kingfisher ...
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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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