1. Intro To Pete Alonzi University of Virginia Library
Research Data Services
February 14, 2017

2. Outline
Installation
Getting our sea legs – terminals, and text editors, and IDEs
Math and variables
Functions
Python Data Types
Loops
Logic
Import
Odds and ends

3. Installation of Python
Two Notes
Language (python) vs language distribution (anaconda)
Python 2 vs Python 3

4. Programming vs Python
For this workshop we are not requiring any previous knowledge of python or of computer programming. As a result we will be explaining fundamental concepts of each. Our emphasis is on the python but we will spend time on programming as well.

5. Brief history of Python - https://www.python.org/
Designed by Guido van Rossum
1991
successor to the ABC language
Python 2.0 was released on October 2000
Python 3.0  was released on December 2008

6. Let’s Open Spyder

7. Programs – “Hello World!”
In programming the classic first program is called “Hello World!”

8. Math and Variables Python knows math!
1+2
Python uses variables to reference things (for example some math).
X = 1+2
The “=“ is special. It doesn’t mean equals to. It means refers to.
Variable

9. Math and Variables Math operations Variable rules + - * / ** % //
* / ** % //
Variable rules
Must start with a letter
Have a type

10. Functions
Functions are prewritten pieces of code that perform one specific task.
Let’s take a look at type(…)
Function code
name
arguments

11. Programs – “Hello World!”
In programming the classic first program is called “Hello World!”

13. Data Types - Strings A string is a string of characters
“apple”
“blue42”
“iamtheverymodelofamodernmajorgeneral”
“7hills”
Helper functions: string.lower(), string.upper()
And many more, check out the online docs

14. Indexing
fruit = ‘ a p p l e ‘

15. Data Types – Strings - Slicing
Reference elements of a string with […:…]
[from:up to but not including]

16. Data Types - Lists Lists are represented: name[…]
Contains a list of elements of various types
You can even have a list of lists
Lots of helper functions
Reference with [...] and can slice too!
Don’t forget tuples: name(…) and immutable

17. Data Types - Dictionary
Dicts are represented: name{…}
Elements are a pair: key:value
The keys are strings and values are anything
Lots of helper functions

18. Loops – FOR For loop syntax: for ___ in ___ :
The first blank is a new variable
The second blank is an iterable
eg: for x in range(10): print x

19. Loops – WHILE While loop syntax: while <boolean>:
The boolean is checked every iteration
eg: while i<10: print i; i+=1

20. If statements Normally your code progresses linearly
Use an if statement for a fork in the road
Syntax: if <boolean>: ______ else: _______
To chain multiples together use elif

21. Import modules
A great feature of python is modularity. Lots of people have developed lots of good modules.
A great module is called numpy
Eg: numpy.random.randn()
But my favorite module is called pandas
Use nltk for text manipulation

22. Import modules
A great feature of python is modularity. Lots of people have developed lots of good modules.
A great module is called numpy
Eg: numpy.random.randn()
But my favorite module is called pandas

23. Comments
Every programming language has a way for you to include text to help explain the code.
In python you can make a comment two ways.
# everything after a # is commented
Everything between ’’’ is a comment ‘’’

24. File input/output (I/O)
Reading from a file

25. File input/output (I/O)
Writing to a file