ling/c sc/psyc 438/538 lecture 3 sandiway fong. administrivia homework 2 graded

LING/C SC/PSYC 438/538

Lecture 3Sandiway Fong

Administrivia

• Homework 2 graded

Today’s Topics

• Homework 2 review– reminder: submit plain text or PDF please

(no .doc/.docx)

• Perl

Short Homework 2 Review

• Is tough sledding an idiom or compositional in meaning?

• Compositional:– Meaning(tough sledding) = Meaning(tough) ⨂

Meaning(sledding)– Literal meaning: "kick the bucket"

• Idiom:– Meaning(tough sledding): explicitly learned and

stored

Short Homework 2 Review

• The chickens are ready to eat• In what way(s) is this sentence structurally

ambiguous?

gardenbetty.com

X eat YX = the chickens

Berkeley Parser

Short Homework 2 Review

• The chickens are ready to eat• In what way(s) is this sentence structurally

ambiguous?

wikipedia

X eat YY = the chickens

Short Homework 2 Review

• John said he dislikes nearly everyone he meets • In what way(s) is this sentence referentially

ambiguous? 1. John said John dislikes nearly everyone John meets2. John said Pete dislikes nearly everyone Pete meets3. John said Pete dislikes nearly everyone John meets4. …

Perl Day

• Learn Perl– Books… see next slide– Online resources• http://learn.perl.org/• we begin with ...• http://perldoc.perl.org/perlintro.html

philosophy: Natural Language Principles in PerlIf a language is designed so that you can ``learn as you go'', then the expectation is that everyone is learning, and that's okay.http://www.wall.org/~larry/natural.html

Perl DayUA has free access to O'Reilly's Safari library:• http://proquest.safaribooksonline.com.ezproxy2.library.arizona.edu/search?

q=perl

Perl arrays and hashes

• Scalars: – strings, numbers (integers, floating point numbers),

references• Arrays:– Store multiple scalars together– Idea: list of scalars– Access by index: 0,1,2,…

• Hash (aka Associative Array):– Like an array except access not through a numeric index– Use user-specified keys

$variable

@variable

%variable

different namespaces:$apple @apple %appleare different data structuresand can co-exist simultaneously

most programming languages will offer youall of these basic data types

Perl Week

Perl Week

Perl Week• Notes on arrays and hashes

– arrays are indexed from 0,1,2,3…– hashes are like arrays with user-defined indexing

(aka associative array or hash table)

– initialization (use round brackets and commas)• @a = (“zero”, “one”, “two”, “three”, “four”);• %h = (“zero”, 0, “one”, 1, “two”, 2, “three”, 3, “four”, 4);

(key/value pairs)

– access to individual elements (square brackets vs. curly braces)• $a[1] “one”• $h{zero} 0

Perl Week

• Notes on arrays and hashes– output

• print @a zeroonetwothreefour• print “@a” zero one two three four• print %h three3one1zero0two2four4

(note: different order)• print “%h” %h (literal, no interpolation)

What happens here?– %pos = ("apple", "n", "speak", "v", "happy", "a", "walk", "n",

"walk", "v");– print $pos{"walk"}, "\n";

(hash keys are unique)

controlled by variable $”default: a space

Perl Week

• Conditionals– if ( @a < 10 ) { print “Small array\n” } else {print “Big array\n” }– Note: @a here is a scalar = size of array– unless (@a > 10) { print “@a\n” }– Note: if size of array a is ≤ 10, it prints the contents of array a

Looping%fruits = ("apple", "green", "orange", "orange", "lemon", "yellow");foreach $fruit (keys %fruits) { print $fruit, " => ", $fruits{$fruit}, "\n” }gives output:lemon => yellowapple => greenorange => orangeNote: apparently

keys %fruits = (“lemon” “apple” “orange”) is an array