1. LING 408/508: Computational Techniques for Linguists
Lecture 22

2. Administrivia Homework 9 graded Python:
cgi-bin: bash scripting requires attention to detail (unfortunately finicky)
that shell script "glue" could access any programming language, e.g. Python
Python:
from a command line calculator to the Natural Language Toolkit (nltk)

3. Homework 9 Example
Use the cgi-bin methods to implement a BMI bash shell script on the webserver.

4. Homework 9 Example

5. Homework 9 Example

6. Next Programming Language
So far, in this course you've been exposed to:
Binary language of the CPU: encoding of numbers and characters (unicode)
Linux (Ubuntu under VirtualBox)
command line: bash shell
bash shell scripting: #!/bin/bash
awk and regular expressions (regex)
html/css
Javascript + DOM
Web client/server model
Now we switch for the rest of the semester to a regular programming course:
Python

7. Term Programming Project
It's time to think about the end of the semester …
Propose a programming project
half of your grade
Send your proposal to me
If I give up the go-ahead, you can start working on it …

8. Why Python? Installed by default on OSX
but you should install and use python3

10. Python on Ubuntu
sudo apt install python3-pip

11. Python on Ubuntu

12. Python resources Many (free) online resources Through UA:
1.5hrs (18 Lessons) QuickStart! - Python uickStart!-Python-Tutorials.htm
8hrs (64 Lessons) Practical Python for Beginners Course thon.htm
Pythonbook (based on Python 2.7):
On course website: pythonbook.pdf

13. Python resources
python.org

14. Python
At the interpreter:

15. Python: Numbers
pythonbook page 53
pythonbook page 54

16. Python: Numbers Python: Javascript: Number data types: int, float
Matters for things like division: /
Javascript:
everything is a floating point number

17. Python: Numbers
import math
math.pi
complex numbers:
import cmath

18. Python range(): produces a list (sequence) range(n) [0,1,..,n-1]
range(start,n) [start,start+1,..,n-1]
range(start,n,step) [start,start+step,…,last]
last=start+k*step < n
range(n,stop,-step) counts down
(pythonbook page 40)

19. Python How about to 2 decimal places?
use raw_input() instead of input() for strings
eval(raw_input()))is equivalent to input()

20. Formatted Output Lots of ways: (Old way)
Notation comes originally from C :
sprintf function

21. Formatted Output %<width>.<precision><type>
<type> = d, f, s
<width> = minimum number of characters; right-justified by default, -width => left-justified 0 = as wide as needed
<precision> = number of places after decimal point
e.g. 02d two digits wide, pad with 0 if needed

22. Formatted Output Newer way:
formatting
Use {} for each argument
(can be numbered, e.g. {0}, {1},… or referenced by keyword {x})
{:width}

23. Python pythonbook page 60: see factorial.py
Python automatically converts to type long int from int (32 bit 2's complement), (page 64–65, section 3.5)
explicit type coercion:
float()
int()
long()
complex(r,i) complex numbers
complex(string)