SAMS Teach Yourself Perl in 24 Hours THIRD EDITION

Workshop

If you've started to figure out the pattern to regular expressions, try this quiz to see what you've learned.

Quiz

1:	If you have lines formatted "x=y", what expression would swap the left and right sides of the expression? s/(.+)=(.+)/$2=$1/; s/(*)=(*)/$2=$1/; s/(.*)=(.*)/$2$1/;
2:	After this code, what's the value in $2? $foo="Star Wars: The Phantom Menace"; $foo=~/star\s((Wars): The Phantom Menace)/; $2 is not set after the pattern match because the match fails. Wars Wars: The Phantom Menace
3:	What does the pattern m/^[-+]?[0-9]+(\.[0-9]*)?$/ match? Dates in the format 04-03-1969 Well-formed numbers such as 45, 15.3, -0.61 Addition-looking patterns: 4+12 or 89+2

Answers

A1:	a. Choice c doesn't include the = symbol in the replacement string ...