(Programming) Languages, Python(3), PythonAnywhere, Canopy

class: center, middle

# (Programming) Languages, Python(3), PythonAnywhere, Canopy

.author[
CORE-UA 109.01, Joanna Klukowska <br>
adapted from slides for CSCI-UA.002 by D. Engle, C. Kapp and J. Versoza
]

---

# Natural Languages

**What are some characteristics of natural languages?**

* meant for communication between people (usually!)
* these are the languages that people speak ([English, Urdu, Catalan, etc.](http://en.wikipedia.org/wiki/List_of_languages_by_name))
* not intentionally designed - evolved naturally / organically
* usually verbose
* room for ambiguity, interpretation, etc.

---

# A Programming Language...

on the other hand ...

* is artificial / synthetic
* is created specifically to communicate __instructions__ to a machine 
* usually has a rigid structure or grammar 
* is usually very strict about __syntax__
* some words / symbols have special meanings
* is usually exact / explicit in its meaning
* information dense; each character counts!
* provides a layer of __abstraction__ between programmer and machine

__This Makes Reading and Writing Programs Much Different From Natural Languages__

---

# Reading a Programming Language

* reading a program requires analysis of a program's __structure__ 
* information density can make comprehension a slow process
* again, meaning is usually unambiguous 
	* behavior / meaning usually backed by formal specifications
	* though language is unambiguous, programmer intent may not be!

# Writing a Program
* easy to introduce minor syntactic errors (you must be careful with syntax and grammar)
* may have multiple implementation possibilities
* may offer constructs for abstraction and preventing repetition
	* potentially further improves on human readability
	* important for refactoring, improving your program, and future maintenance
* don't necessarily have to know entire language to write a program!

---
# Sooo Many Programming Languages...

__(You could even make one yourself!)__

These Are 20 of the Most Used Languages Today
(At least, according to [TIOBE](http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html), August 2017)

<table style='text-align:left;margin:auto;'>
<tr>
	<td width="33%">
		<ol>
		<li>Java</li>
		<li>C</li>
		<li>C++</li>
		<li>C#</li>
		<li><strong>Python</strong></li>
		<li>Visual Basic .NET</li>
		<li>PHP</li>
		</ol>
	</td>
	<td width="33%">
		<ol start="7">
		<li>JavaScript</li>
		<li>Perl</li>
		<li>Ruby</li>
		<li>Swift</li>
		<li>Delphi</li>
		<li>VisualBasic</li>
		</ol>
	</td>
	<td width="34%">
		<ol start="14">
		<li>Assembly</li>
		<li>R</li>
		<li>Go</li>
		<li>MATLAB</li>
		<li>Objective-C</li>
		<li>Scratch</li>
		<li>Dart</li>
		</ol>
	</td>
</tr>
</table>

__Python__ is a friendly high-level programming language that we will be using in this class.

---

# Which Python

* Python currently has two active versions 2.x and 3.x
* we will be using the version 3.x in this class

---

__Warning__: Many online resources do not mention the version 
of Python that they are refering to. The two versions are not always
compatible and you need to be very careful to always use 3.x in this class.

---

# How will we write Python?

__Python programs are just text__
* we will use text editors to edit the programs
* the files end in a `.py`, for example, `hello.py` or `problem1.py`

Note: we cannot use word processors like Microsoft Word or Pages. Why? Because they
are not just text editors; they save a lot of information about text formatting, structure 
of documents, etc.

__Which text editors will we use to write programs?__
* well ...
* we will use one of the two __IDEs__ ( = Integrated Development Environment) instead
of just a plain text editor
* why? 
* because an __IDE__ comes with many features, in addition to a text editor, that 
help programmers

---

# Which IDEs will we use?

.left-column2[ 
__PythonAnywhere__

![PythonAnywhere logo](https://www.pythonanywhere.com/static/anywhere/images/logo-234x35.png)

* [https://www.pythonanywhere.com/](https://www.pythonanywhere.com/)
* cloud-based / web-based, not on your own computer
* 👍 does not require any installation 
* 👍 you can use it from any computer (lab, friend, library)
* 👎 requires that you are connected to the Internet 
* 👎 tends to be slow and there are limits on usage with a free version
* 👎 does not support graphics that just open up (like a plot) - you need to 
save those to files
]

.right-column2[
__Conopy__

![Canopy logo](https://static.enthought.com/etw/img/enthought-logo-w-tag.png?8feb477)

* [https://www.enthought.com/products/canopy/](https://www.enthought.com/products/canopy/) 
* on your own computer 
* requires installation on your computer
* 👎 if anything happens to your own computer, you cannot access it
* 👍 no need for the Internet connection (except for the installation time)
]
  
--

.below-column2[
We will use both of them to take advantage of all the  👍 and minimize problems 
resulting from  👎.
]