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Introduction to Python

LING 5200Computational Corpus LinguisticsMartha Palmer

LING 5200, 2006 BASED on Kevin Cohen’s LING

52002

What's a programming language? Structural elements Way of converting a text file to

instructions for the machine

LING 5200, 2006 BASED on Kevin Cohen’s LING

52003

What's a programming language? lexicon syntax

Vs. natural languages: no ambiguity

LING 5200, 2006 BASED on Kevin Cohen’s LING

52004

What does a program do?

Take in data (input) Do something with it (processing) Produce output

LING 5200, 2006 BASED on Kevin Cohen’s LING

52005

What does a program do?

Input your regex one or more files switches

For each line in each file, determine whether or not it matches your regex

Tell you about it

egrep '^[0-9]+\/' epw.cd

LING 5200, 2006 BASED on Kevin Cohen’s LING

52006

Producing output

print "hello, world"

LING 5200, 2006 BASED on Kevin Cohen’s LING

52007

Producing output

print "hello, world"

verb

LING 5200, 2006 BASED on Kevin Cohen’s LING

52008

Producing output

print "hello, world"

noun (object)

LING 5200, 2006 BASED on Kevin Cohen’s LING

52009

Producing output

#!/usr/local/bin/python

print "hello, world"

LING 5200, 2006 BASED on Kevin Cohen’s LING

520010

Producing output

Filename: helloWorld.py What do the file's permissions need to

be?

LING 5200, 2006 BASED on Kevin Cohen’s LING

520011

Producing output

babel>python helloWorld.py

hello, worldbabel>

LING 5200, 2006 BASED on Kevin Cohen’s LING

520012

Producing output

#!/usr/local/bin/python

print "hello, world\n";

"escape" character

LING 5200, 2006 BASED on Kevin Cohen’s LING

520013

Producing output

\t tab \n "newline"

LING 5200, 2006 BASED on Kevin Cohen’s LING

520014

Comments

#1 use for comments: adding notes to yourself/other programmers

# the purpose of this program

# is to print "hello, world" to

# the screen.

# author: mpalmer@colorado.edu

# 303-492-1300

LING 5200, 2006 BASED on Kevin Cohen’s LING

520015

Comments

#!/usr/local/bin/perl

# the purpose of this program

# is to print "hello, world" to

# the screen.

# author:mpalmer@colorado.edu

# 303-492-1300

# do the actual printing

print "hello, world\n"

"Commenting" your code

LING 5200, 2006 BASED on Kevin Cohen’s LING

520016

Comments

Other use: causing Python to ignore a line

# print "hello, world\n";print "goodbye, cruel world\n";

"Commenting out" a line of code

LING 5200, 2006 BASED on Kevin Cohen’s LING

520017

Comments

Own-line or end-of-line formats

# print it

print "hello, world\n"

print "hello, world\n" # print it

LING 5200, 2006 BASED on Kevin Cohen’s LING

520018

Producing output

I'd like to print something different every once in a while…

$name = “Martha”

print name

LING 5200, 2006 BASED on Kevin Cohen’s LING

520019

Variables

Name Contents Location in memory

LING 5200, 2006 BASED on Kevin Cohen’s LING

520020

Variables

Name (name) Contents (Kinder) Location in memory (13025)

$name

LING 5200, 2006 BASED on Kevin Cohen’s LING

520021

Using +

name = “Martha"

print "hello, ” + name

LING 5200, 2006 BASED on Kevin Cohen’s LING

520022

Python for Linguists

http://mime.colorado.edu/~bethard/Python%20for%20Linguists/Python-1.pdf