slides.md

title: Meet, Python! content_class: flexbox vcenter centered

World's easiest and arguably most powerful programming language.

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title: Who uses Python? content_class: flexbox vcenter centered

and many, many more. . .

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• Very-high-level, interpreted, loosely and dynamically typed, object-oriented

• Clean, readable syntax

• Comfortable level of abstraction, automatic memory management

• Does not force object orientation

• Extensive collection of standard modules, great community support

• Can be, and is, used for a large number of application types

• Easily extensible, plays nice with applications written in other programming languages

• Easy to learn, get started, and build things, has common sense

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source: xkcd.com

This is a title with the event branding.

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title: Common Sense? class: fill

#include <iostream>
using namespace std; 
int main()
{
cout << "Hello, world!" << std::endl;
    return 0;
}

public class HelloWorld {
	public static void main(String [] args) {
		System.out.println("Hello, world!");
        }
}

How about, NO.

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print "Hello, World!"

• Clean, comprehensible syntax.
• No braces. Uses tab spaces as delimiters.

Impressed already?

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Set up Python on your computer.
Fire up the interpreter.

$ python
or
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Your Python shell can be used to do some real quick calculations. Don't reach out for your calculator ever again.

>>> 3 + 2
5
>>> 98 - 56
42
>>> (60 - 57) * 11
33
>>> (124 - 88) / 9
4

Looks cool, huh?

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Arithmetic

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>>> 57 / 8					# integer division by default
7
>>> 57.0 / 8				# coercion to float division
7.125
>>> PI = 3.14				# PI is a variable
>>> r = 2.5
>>> area = 2 * PI * r**2	# ** is used for exponentiation
>>> area
39.25
>>> x = 1
>>> y = z = 5				# multiple variable assignment
>>> X + y * z
Traceback (most recent call last):		# Drats! We have an error!
  File "<input>", line 1, in 
NameError: name 'X' is not defined		# variables are case-sensitive!
>>> x + y * z
26

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title: Imaginary numbers too! class: fill

Complex numbers : real + imag j

>>> z = 4 + 2j
>>> z
(4+2j)				# complex number tuple
>>> z.real			# property
4.0
>>> z.imag
2.0
>>> z.conjugate()	# method
(4-2j)
>>> abs(z)			# abs() is a built-in method in Python
5

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>>> x, y = 42, 6.9	# multiple inline assignments
>>> float(x)		# converts to floating point
42.0
>>> int(y)			# converts to an integer
6
>>> round(y)		# rounds off to the nearest integral number, returns a float
7.0
>>> long(x)			# converts to long int
42L
>>> max(x, y)
42
>>> min(x, y, 0, -3)
-3

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Strings

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>>> 'CampusHash'
'CampusHash'
>>> "Hello, world!"
'Hello, world!'
>>> "And then everyone shouted, 'We love CampusHash!'"		# nested quotes
"And then everyone shouted, 'We love CampusHash!'"
>>> 'I said, "Well, that\'s great."'				# escaping with \
>>> person, emotion, thing = "Minions", "love", "banana"
>>> person+emotion+thing
'Minionslovebanana'
>>> person + ' ' + emotion + ' ' + thing + '.'
'Minions love banana.'
>>> thing * 5
'bananabananabananabananabanana'

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title: Let's 'print' something! class: fill

>>> print 'Gru'
Gru
>>> movie = 'Despicable Me'
>>> movie
'Despicable Me'
>>> print movie
Despicable Me		# no quotes!

• print is not a function. It is an operator.
• Anything that you operate print on, will be printed to the standard output.

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title: Anatomy of a String class: nobackground content_class: flexbox vcenter centered

Tip : Google for 'Monty Python's Flying Circus'.

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title: Not just your regular String class: fill

• There is no char in Python. Only str.
• Strings are immutable, i. e., they cannot be changed.
• Strings support splicing.
• Lots of in-built methods and properties to operate on strings.

>>> name = "Minion"
>>> name[3]
'i'
>>> name[3] = 'x'
Traceback (most recent call last):
  File "<input>", line 1, in 
TypeError: 'str' object does not support item assignment
>>> name[::-1]		# This one's magic!
'noiniM'

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Data Structures: Lists


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List is a compund datatype.

It is analogous to an array.

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title: Lists - Feature Check
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- Lists are collections of items (strings, integers, or even other lists).
- Each item in the list has an assigned index value.
- Lists are enclosed in [ ].
- Each item in a list is separated by a comma.
- Unlike strings, lists are mutable, which means they can be changed.

>>> fruits = ['apple', 'banana', 'orange']
>>> fruits[0]
'apple'
>>> mix = ["1", "hello", 2, "world"]
>>> mix[-1]
'world'


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Data Structures: Dictionaries


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Dictionaries are hash tables.


title: Dictionaries - Feature Check
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Dictionaries are collections of items that have a "key" and a "value".


Python dictionaries are also known as associative arrays or hash tables.


They are just like lists, except instead of having an assigned index number,
you make up the index.


Dictionaries are unordered, so the order that the keys are added doesn’t
necessarily reflect what order they may be reported back.


Use {} curly brackets to construct the dictionary.


Look up the value associated with a key using [].


Provide a key and a value.


A colon is placed between key and value (key:value).


Each key must be unique and each key can be in the dictionary only once.



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Tuples and Sets


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Functions


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A function is something you can call which performs an action and returns a value.


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A function in Python must be defined before it’s used.


Create a function by using the keyword “def” followed by the functions name and
the parentheses ().


The function has to be named plus specify what parameter it has (if any).


The keyword "def" is required and must be in lowercase.


The name can be anything you like.


The end of the line has to end with a colon (:)


The function often ends by returning a value using return.


The code inside the function must be indented.



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Loops


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Loops allow us to do similar things many times.


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Conditions and Comparisons


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In-built Functions


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Classes


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Classes are definitions for objects.


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Object-orientation


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Everything is an object in Python.


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Modules and Packages


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I ♥ questions!