LING/C SC/PSYC 438/538

LING/C SC/PSYC 438/538 Lecture 6 Sandiway Fong

Today’s Topic • Homework 2 out today • due next Thursday by midnight • submit one file only (preferably PDF) • Subject line: Your Name 538/438 Homework 2 • Perl Recap • file I/O, references, arrays • Perl • iteration • Perl Modules • Homework 2

Perl Recap • File I/O open($txtfile, $ARGV[0]) or die "$ARGV[0] not found!\n"; while ($line = <$txtfile>) { print "$line"; } • References: • $aref = [ ITEMS ] $aref is a reference to an array • @{$aref} the array • ${$aref}[0] first element of the array • $href = { ITEMS } $href is a reference to a hash • %{$href} the hash • ${$href}{key} the value associated with key in the hash

Perl Arrays • Functions on arrays: • From the front: shift array unshift array, list • From the back: pop array push array, list generalized function

Perl Strings and Arrays • Strings and arrays chomp vs. chop split a string into words

Iteration • We’ve already seen for/foreach: foreach $var (@array) { .. do something with $var .. } • for-loop: @words = qw(this is a short sentence); for (my $i=0; $i<$#words; $i++){ do something with $i and @words … } @words

Sorting revisited • From two lectures ago… • Sort (cmp - strings, <=> - numeric): • Perl version 5.16 onwards has fc (fold case) function • Unicode compatible • Unicode::CaseFold module has a function fc • Standard function is called lc (lowercase) • Works for ASCII • Also functions uc/ucfirst

Experiment • Unicode encoding (utf-8)

Module not downloaded bash-3.2$ perltest.perl Can't locate Unicode/CaseFold.pmin @INC (@INC contains: /Library/Perl/5.12/darwin-thread-multi-2level /Library/Perl/5.12 /Network/Library/Perl/5.12/darwin-thread-multi-2level /Network/Library/Perl/5.12 /Library/Perl/Updates/5.12.4 /System/Library/Perl/5.12/darwin-thread-multi-2level /System/Library/Perl/5.12 /System/Library/Perl/Extras/5.12/darwin-thread-multi-2level /System/Library/Perl/Extras/5.12 .) at test.perl line 1. BEGIN failed--compilation aborted at test.perl line 1.

cpanm • Example (command line): • cpanm Unicode::CaseFold • installing cpanminus (cpanm) • cpanminus is a script to get, unpack, build and install modules from CPAN and does nothing else. • assume command line program curl (cURL) to get cpanm from the internet • curl is a command line tool for getting or sending files using URL syntax

cpanm

cpamn bash-3.2$ which cpanm bash-3.curl -L http://cpanmin.us | perl - --sudo App::cpanminus % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 303 0 303 0 0 56 0 --:--:-- 0:00:05 --:--:-- 1553 100 262k 100 262k 0 0 22916 0 0:00:11 0:00:11 --:--:-- 64374 --> Working on App::cpanminus Fetching http://www.cpan.org/authors/id/M/MI/MIYAGAWA/App-cpanminus-1.7000.tar.gz ... OK Configuring App-cpanminus-1.7000 ... OK Building and testing App-cpanminus-1.7000 ... Password: OK Successfully installed App-cpanminus-1.7000 1 distribution installed bash-3.2$ which cpanm /usr/local/bin/cpanm bash-3.2$

Cpanm Unicode::CaseFold bash-3.2$ cpanm Unicode::CaseFold ! ! Can't write to /Library/Perl/5.12 and /usr/local/bin: Installing modules to /Users/sandiway/perl5 ! To turn off this warning, you have to do one of the following: ! - run me as a root or with --sudo option (to install to /Library/Perl/5.12 and /usr/local/bin) ! - Configure local::lib your existing local::lib in this shell to set PERL_MM_OPT etc. ! - Install local::lib by running the following commands ! ! cpanm --local-lib=~/perl5 local::lib && eval $(perl -I ~/perl5/lib/perl5/ -Mlocal::lib) ! --> Working on Unicode::CaseFold Fetching http://www.cpan.org/authors/id/A/AR/ARODLAND/Unicode-CaseFold-0.03.tar.gz ... OK Configuring Unicode-CaseFold-0.03 ... OK Building and testing Unicode-CaseFold-0.03 ... OK Successfully installed Unicode-CaseFold-0.03 1 distribution installed No root access

Cpanm Unicode::CaseFold bash-3.2$ sudocpanm Unicode::CaseFold --> Working on Unicode::CaseFold Fetching http://www.cpan.org/authors/id/A/AR/ARODLAND/Unicode-CaseFold-0.03.tar.gz ... OK Configuring Unicode-CaseFold-0.03 ... OK Building and testing Unicode-CaseFold-0.03 ... OK Successfully installed Unicode-CaseFold-0.03 1 distribution installed With root access

Appendix: command line tools • For the mac (10.8), command line tools are not installed even if you install XCode

Appendix: command line tools • Xcode: Preferences

Appendix: command line tools • make

Homework 2 Question 1 (10pts) • Create a file data.txt (example): • I saw the cat on on the mat. • The the the cat sat on the mat. • Write a Perl program that detects repeated words (many spell check/grammar programs can do this) • Your program should read in data.txt and print a message stating the line number, the repeated word and its position if one exists. Example output: • perlrepeated.perldata.txt • Line 1: word 5, “on” repeated 2 times • Line 2: word 1, “the” repeated 3 times • Submit your program and examples of its output Note: case

Homework 2 • Question 2: (10 pts) • describe how a repeated word program could stop flagging legitimate examples of repeated words in a sentence • Examples: • I wish that that question had an answer • Because he had had too many beers already, he skipped the Friday office happy hour

Homework 2 • Microsoft Word:

LING/C SC/PSYC 438/538