1. LING/C SC/PSYC 438/538
Lecture 3
Sandiway Fong

2. Administrivia Homework 3 Make Up:
If you missed HW3, there is an alternate HW3. me.
Last Time:
Quick Quiz (you should have received an back from me)
Today's class:
Quick Quiz Review
Quick Homework 4
perlintro …

3. Quick Quiz on Chapter 1

4. Quick Quiz on Chapter 1 I made her duck. 1. Eye made her duck.
Eye maid her duck.
I maid her duck.
Label: Short for:
PRP pronoun
PRP$ possessive pronoun
NN common noun
VBD verb past tense
NP noun phrase
VP verb phrase
S sentence

5. Quick Quiz on Chapter 1 I made her duck. Eye made her duck.
Label: Short for:
PRP pronoun
PRP$ possessive pronoun
NN common noun
NNP proper noun
VBD verb past tense
VBZ verb 3rd pers. sg. present
NP noun phrase
VP verb phrase
S sentence
Quick Quiz on Chapter 1
I made her duck.
Eye made her duck.
Eye maid her duck.
I maid her duck.

6. Quick Homework 4
Q1: Explain what's supposed to be funny about this?

7. Quick Homework 4 1. Commas are important people.
Q2: Run the these two sentences on the Berkeley Parser. Critique the parse. (
Q3: Compare with the Google Parser. Critique the dependency parses. (

8. Quick Homework 4 Resources Universal dependencies relations:
Universal Part of Speech (POS) tags:
Tree labels
VP = Verb Phrase, S = Sentence, SBAR = Embedded Sentences, NP = Noun Phrase, PP = Prepositional Phrase. ADJP = Adjectival Phrase.
Tree POS tags:
DT = Determiner, JJ = Adjective, JJR = Adjective (Comparative Form), NN = Common Noun, NNS = Common Noun (plural), NNP = Proper Noun, VB = Verb (base form), VBD = Verb (past tense), IN = Preposition, PRP$ = Possessive Pronoun.
More here:

9. Quick Homework 4 email me your answers by the end of Wednesday Rules:
Subject: 438/538 Your Name Homework 1
One PDF file only (include any diagrams) – no multiple attachments, no Word documents

10. Programming From last time…
Search: how do I look for patterns (regex) in a text corpus?
grep -Eo ':\s+Yea[^h]' 2150Mon.txt
perl -nle 'print $1 if /(.):\s+Yep/' 2149Mon.txt 
command line options: -nle
-n loop over lines of the input file
-l print newlines
-e execute code from command line

11. Perl http://perldoc.perl.org/perlintro.html One-liner:
perl -e 'PerlCode'
Notes from the tutorial:
whitespace not always necessary, e.g.
print"Hello class!\n”;
is fine, but good idea to consistently use spacing (not just for readability)
variable names must not begin with a number (use a letter), so
$538students is out
$students538 is ok
error messages are frequently uninformative (and sometimes misleading), e.g.
Bareword found where operator expected at example.prl line 3, near "$538students"
(Missing operator before students?)
error not associated with the variable starting with a number
“Nanny mode”: helps with debugging:
makes you declare variables with my

12. print as a statement vs. function
Perl
Python3
Same behavior, different assumptions about end of line (\n) from these two programming languages
escape character
Note also the differences in syntax:
(..) in Python3, no parentheses (needed) in Perl
; need to separate the statements in Perl, none in Python

13. Perl vs. Python3
Scalars: (basically things that take up one 32/64 bit word of memory)
variables begin with ($) - no such type requirement in Python
Numbers (integer, floating point)
Python includes complex numbers (cmath library)
Strings (double ".." or single quoted '..')
References (pointers to (non-)scalars)

14. Perl vs. Python3 Variable interpolation Perl: Python3: Python2.7:
print "My name is $name\n";
print "My name is \$name\n";
print 'My name is \$name\n';
Python3:
print("My name is", name)
Python2.7:
Note: white spacing

15. Perl Arrays like a simple ordered list… (in Python, we use a list)
Literal:
@ARRAY = ( … , … , …) (round brackets; comma separator)
Python: array = [… , … , … ]
Access:
$ARRAY[ INDEX] (zero-indexed; negative indices ok; slices ok)
Python: array[index]
Index of last element:
 $#array (a scalar)
Python: array[-1]
Coercion
@ARRAY = number of elements in scalar context
Python: len(array)
Built-in functions:
$ELEMENT; $ELEMENT, $OFFSET, $LENGTH, $ELEMENT
$ELEMENT above can
Python: array.sort(), array.reverse()
Built-in arrays:
@ARGV (command line arguments)
@_ (sub(routine) arguments)

16. Exercises If you’re new to programming, practice using Perl
read the intro and run all the examples!