Some Advanced Regular Expression handling (Perl)

What are Regular Expressions? example from a Well House Consultants training course
More on What are Regular Expressions? [link]

This example is described in the following article(s):
• Running a piece of code is like drinking a pint of beer - [link]

Source code: mare Module: Q801

# More regular expression stuff!
# A revision for Perlers!

# Set up a string to analyse -----------------------

$addy = "404, The Spa, Melksham, SN12 6QL, UK and 48, Spa Road, ".
        "Melksham, SN12 7NY for the training centre. Richard ".
        "is from rg6 7pj ...";

# Sometimes it's easier to save a regular expression in a variable
# Do make sure to use ' not " if you have things like \s and \n around!
# 'one or two letter, one or two digits, some space, a digit, 2 letters'

$re_postcode = '(([A-Z]{1,2})[0-9]{1,2}\s+[0-9][A-Z]{2})';

# Matches are saved in $1 and $2

while ($addy =~ /$re_postcode/gi) { # global, ignore case
        print "yes - ",uc($1)," - $2 area \n";
}

# All non-overlapping matches! - list context

@gotten = $addy =~ /$re_postcode/gi;
print ("@gotten\n");

# If you want to keep them after the next re match, name them!

($whole,$zone) = $addy =~ /$re_postcode/i;
print "Zone is $zone from $whole\n";

# When you match, you split your incoming line into three.

print "The bit before ",$`,"\n";
print "The bit after ",$',"\n";
print "The bit that matched ",$&,"\n";

# We had better correct postcodes to make them all capital!

$addy =~ s/$re_postcode/uc($1)/eig; # e - execute as code
print "Now reads $addy\n";

__END__

It runs like this:

Dorothy-2:perl grahamellis$ perl mare
yes - SN12 6QL - SN area
yes - SN12 7NY - SN area
yes - RG6 7PJ - rg area
SN12 6QL SN SN12 7NY SN rg6 7pj rg
Zone is SN from SN12 6QL
The bit before 404, The Spa, Melksham,
The bit after , UK and 48, Spa Road, Melksham, SN12 7NY for the
        training centre. Richard is from rg6 7pj ...
The bit that matched SN12 6QL
Now reads 404, The Spa, Melksham, SN12 6QL, UK and 48, Spa Road,
        Melksham, SN12 7NY for the training centre. Richard is
        from RG6 7PJ ...
Dorothy-2:perl grahamellis$

Learn about this subject

This module and example are covered on the following public courses:
* Regular Expressions
* Intermediate Python
Also available on on site courses for larger groups

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