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Welcome to the Saturday afternoon projects section of the Philadelphia Python Workshop! During our first project session from 1-2pm, we'll work through a WordPlay exercise to practice manipulating and matching strings. During our second project session, we'll use the Twitter API to write the basic parts of a Twitter client. You also have the option of reviewing basic concepts instead of participating in the Twitter project.
===Python Wordplay Project Instructions===
Here are the [[Philadelphia Python Workshop/Projects/Wordplay|Wordplay Project Instructions]].
==Twitter==
<table>
<tr>
<td>
[[File:Twitter.png|100px]]<br />
<center><b>Twitter</b></center>
</td>
<td>
Use the Twitter API to write the basic parts of a Twitter client. See what your friends are tweeting, get trending topics, search tweets, and more.
</td>
</tr>
</table>
===Twitter goals===
* practice for loops
* practice using functions
* practice implementing functions
* see what it's like to use an API
* have fun collecting data from Twitter
===Concept review===
====Indentation reminder====
In Python, indentation matters. Everything is indented by a multiple
of some number of spaces, often 4.
In <code>if</code> statements, you indent everything you want to be run if the if
conditional is <code>True</code>. For example:
<pre>
>>> James = 35
>>> Alice = 30
>>> if James > Alice:
... print "James is older than Alice."
...
James is older than Alice.
>>></pre>
Because James really is older than Alice, the <code>if</code> conditional is <code>True</code>,
so Python does execute the code indented under the if line. In this
case we print "James is older than Alice."
<pre>
>>> James = 35
>>> Alice = 30
>>> if James < Alice:
... print "James is younger than Alice."
...
>>></pre>
Because James is not older than Alice, the <code>if</code> conditional is <code>False</code>, so
Python does not execute the code indented under the if line.
In for loops, you indent everything you want to be run each loop For
example:
<pre>
>>> names = ["Jessica", "Adam", "Liz"]
>>> for name in names:
... print "Hello " + name
...
Hello Jessica
Hello Adam
Hello Liz</pre>
The <code>print</code> line is indented 4 spaces under the <code>for</code>. That's how
Python knows to execute the print line for every name in names.
====Functions====
Let's review what we know about functions:
* They do some useful bit of work.
* They let us re-use code without having to type it out each time.
* They take input and possibly produce output (we say they return a value). You can assign a variable to this output.
* You define a function using the def keyword.
* You call a function by using its name followed by its arguments in parenthesis.
Here's an example:
<pre>
>>> def add(x, y):
... return x + y
...
>>> add(1, 2)
3
>>> add(-1, 1)
0
>>> add(.5, .75)
1.25</pre>
====pass====
<code>pass</code> is a keyword that just means "do nothing". It most often shows up
as a place-holder for code that doesn't exist yet. For example:
<pre>
>>> def testFunction():
... pass
...
>>></pre>
====Imports====
Imports look like this:
<pre>
>>> import random
>>> import time</pre>
In the above example, <code>random</code> and <code>time</code> are both Python modules. Modules
are Python files outside of the current Python file that contain
Python code, like functions and variables. You can use code from
modules by first importing the module. Here's an example from the
<code>random</code> module:
<pre>
>>> import random
>>> random.randint(0, 10)
7
>>> random.randint(0, 10)
6
>>> random.randint(0, 10)
1
>>> random.randint(0, 10)
3
>>> random.randint(0, 10)
4
>>> random.randint(0, 10)
9</pre>
<code>randint</code> is a function in the <code>random</code> module. It takes a lower bound as
the first argument and an upper bound as the second argument and
returns a random integer between those bounds.
===Python Twitter library functions we will use===
A library provides a collection of functions for you, and defines a contract for using those functions. Here are the functions in the python-twitter library that will be useful for the project:
<code>api.GetSearch(searchString)</code>
Given a string to search for, this function will return a list of tweets matching that search string.
<code>api.GetUserTimeline(username)</code>
Given a username, this function will return a list of tweets belonging to that username.
===Python Twitter Project Instructions===
Here are the [[Philadelphia Python Workshop/Projects/Twitter|Twitter Project Instructions]].
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