What is Python? - JMU CS Department

What is Python?

Python 101

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Object-oriented, rapid prototyping language

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Multi-purpose: Web, GUI, scripting, science, etc.

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Interpreted and interactive; very easy to learn

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Strongly typed and dynamically typed

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Focus on readability and productivity

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Extensive standard library and community

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CPython, Jython, IronPython, PyPy, etc.

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Home page: http://www.python.org/

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Who uses Python? I

Google (various projects)

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NASA (several projects)

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NYSE (one of only three languages “on the floor”)

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Industrial Light & Magic (everything)

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Yahoo! (Yahoo mail & groups)

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RealNetworks (function and load testing)

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RedHat and Ubuntu (Linux installation tools)

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LLNL, Fermilab (steering scientific applications) More success stories at http://www.pythonology.com/

Python 101

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Python vs Java Python

Java

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Dynamically typed (assign names to values)

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Statically typed (must declare variables)

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Concise: “expressing much in a few words; implies clean-cut brevity, attained by excision of the superfluous”

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Verbose: “abounding in words; using or containing more words than are necessary”

# open the file d . txt myFile = open ( " d . txt " )

import java . io .*; ... // open the file d . txt BufferedReader myFile = new BufferedReader ( new FileReader ( " d . txt " ));

http://pythonconquerstheuniverse.wordpress.com/category/java-and-python/ Python 101

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Some Basics I

Indentation matters (no braces!)

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Type matters (must be consistent)

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Comments start with a #

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Strings use ’s or "s (or """s)

I print I None

(vs System.out.println)

≈ null, self ≈ this

I and, or, not I [1, 2, 3]

Python 101

instead of &&, ||, !

is a list (≈ ArrayList)

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Discete Math Example """ Simple demo of the Caesar Cipher . """ def encrypt ( msg , k ): """ Shifts msg by k letters , ignoring spaces . """ ans = " " for c in msg : if ’a ’