-Last updated 23-January-2023

Who am I?

Erich Purpur
Research Librarian for Science & Engineering
I'm a librarian here at UVA Research Data Services

-I'm a liaison to various engineering departments. Basically, if they need stuff from the library I try to make it available for them. I do quite a bit of teaching both in one off workshops like this, ongoing series (PhD+), and for-credit courses. I teach courses releated to python programming and Geographic Information Systems (GIS) I also sometimes help people with GIS (Geographic Information Systems) projects and programming-related questions. And do various side projects as they arise.
- [email protected]
- Brown Science & Engineering Library office i046
Feel free to interrupt with questions!

Welcome to the UVA Library

Other Upcoming Workshops

Workshop	Date	Time
Intro to Version Control w/ Git + Github	Wednesday 1/25	10:00 - 11:30
Intro to Python	Wednesday 2/1	12:00 - 1:30
Intro to Regular Expressions	Wednesday 2/8	10:00 - 11:30
Data Analysis in Python with Matplotlib and Pandas	Wednesday 2/8	10:00 - 11:30
Python Natural Language Processing / Sentiment Analysis	Wednesday 2/15	12:00 - 1:30
Geospatial Data + Mapping in Python	Wednesday 2/22	10:00 - 11:30
Python and APIs	Wednesday 3/1	12:00 - 1:30
Python Web Scraping	Wednesday 3/15	12:00 - 1:30

Getting Anaconda + Python (this will take some time)

Windows
Mac

Getting the files we are working with today

Go here: https://github.com/epurpur/python-intro
Click "Clone or Download" (green button in upper right corner)
Click "Download Zip"
Unzip that directory and move it somewhere that is easy to find (like your Desktop, for example)

Goals for Today

Get python running
Learn some fundamentals
Learn how to help yourself (Most Important!)

Outline

Strings
Print Statement
Numbers (Int and Float)
Errors
Functions (Built-ins and custom)
Lists, Loops, Booleans, Indexing
Dictionaries
Import
Conditional Statements
Mutable vs. Immutable data types

What is Python?

From www.python.org: "Python is an interpreted, object-oriented, high-level programming language with dynamic semantics. Its high-level built in data structures, combined with dynamic typing and dynamic binding, make it very attractive for Rapid Application Development, as well as for use as a scripting or glue language to connect existing components together. Python's simple, easy to learn syntax emphasizes readability and therefore reduces the cost of program maintenance."

Python is a general purpose programming language used for a huge variety of purposes. It's user community is growing rapidly! (https://stackoverflow.blog/2017/09/06/incredible-growth-python/)

Difference between R and Python? (Simplified)

They are both open source programming languages
Python is general purpose while R is focused on statistics and data analysis
However, R has grown hugely and has become much more wide ranging
You can also do stats with Python. Many packages available
- NumPy
- SciPy
- Pandas

A brief history

Designed by Guido van Rossum
version 1.0 1994
version 2.0 2000
version 3.0 2008 (we are currently in python version 3.11)
logo
anaconda logo

Let's Get to It (hopefully everyone is done installing)

We are using Anaconda/Spyder today as it seems to be widely used throughout UVA. Adapted for data scientists
Spyder is a Programming IDE (Integrated Development Environment)
- text editor
- variable explorer
- console
- control icons

Strings

A string is a 'string' of characters
- 'apple' # letters
- 'blue42' # letters and numbers
- 'i am the very model of a modern major general' # spaces are fine
- '7 hills' # it can even start with a number

Comments

We also introduce comments here, the computer will ignore everything after the '#' symbol. There are other forms but we'll see them later on.

Variables

You can "save" things as variables. For those curious as to what's going on under the hood...in python a variable is actually just a pointer to the location in memory where the object lives.

a = 'apple'
- a is the variable
- = is the assignment operator
- 'apple' (a string) is the object assigned to a
Important Note: the assignment operator is not like an equals sign
- a=5
- a=7
  - totally works, a was just reassigned to point to 7

Error Messages

Tell you when (and hopefully where) your code breaks.
Some are more readable and helpful than others
Read them from the bottom up

Functions

print(a) # this function will show us what a points to
we know that print is a function because there is no space between print and the "("
format of a function: name(arguments)
we say we "call" a function
this is super important in python the way to spot a function is no space before a "(" and a letter or number
- python built-in functions
- print(...)
- type(...)
- pow(...)
- in an equation you may see 5*(2+3), you won't seet 5(2+3) (try it and see what happens)

Indexing

for objects with an order you can access individual elements
indexing
you can also pull out slices
- syntax [X:Y]
  - starting at X
  - upto but not including Y

Lists

represented like functions but with [...]
there is an order to the items
the items can be of any type

Dictionary

represented like lits but with {...}
there is no order to items
items contain two pieces: a key and a value represented key:value and the key must be a string

loops - used when you want to repeat code

for loop
- for X in Y: << code >>
  - X is a new variable created on the spot
  - Y is some preexisting iterable
  - << code >> is a block of code you want to repeat
  - eg: for x in range(10): print(x)
while loop
- while Z: << code >>
  - Z is a boolean
  - << code >> is a block of code you want to repeat
  - eg: while i<10: print i; i+=1

if statements

example
- if X: << code A >>
- else: << code B >>
  - X is a boolean
  - << code A >> is some code
  - << code B >> is some code, could be the same

Import

This is an important topic

The import command let's you bring in code from another file and use it
one example: random number generation
- import random
  - random.randint(0,10)
Sometimes packages needed to be installed (3rd party packages) *pip - (https://pip.pypa.io/en/stable/installing/) *conda - (https://conda.io/docs/)

Mutablility

Some data types can be changed, others can't
Many reasons for this, a big one is performance
- Mutable data types (such as lists) are costly to CPU processingn power
- Immutable data types (like arrays) take less memory and processing power

Scripting vs Programming

It's a matter of modularity. Programs are designed to be modular and work with other programs. Scripts are designed to be single use.

How to Help Yourself and Learn More

Learning Resources

Pick up a book, there are many available through the UVA library website * Learn Python 3 the Hard Way (Available for free through UVA libraries) * Link here
Phd+ Course Materials * All resources available online for free! * https://learning.rc.virginia.edu/courses/python_introduction/
Other resources available at UVA * Research Data Services - StatLab Fellows * https://data.library.virginia.edu/statlab/ * [email protected] * Research Computing - Provides high performance computing expertise * https://www.rc.virginia.edu/

Self Help via the Internet

Google * Ex: "How to make dictionary python" * Ex: "python decorators"
Stack Overflow (https://stackoverflow.com/) * A question/answer site for programming questions (actually, not just programming any more) * Not only python * DO NOT just ask questions, do your research first! * Odds are very high someone has already asked your question, especially as a novice
Youtube - Corey Schafer (https://www.youtube.com/channel/UCCezIgC97PvUuR4_gbFUs5g) - If you have a question about a python programming concept, Corey Schafer has covered it
Practice Python (http://www.practicepython.org/) * Coding challenges for programmers of all levels
Python Tutor (http://pythontutor.com/) * Visualize what your code is doing step-by-step * Has limitations once you start importing libraries

damichalek / python-intro Goto Github PK

python-intro's Introduction