#!/usr/bin/env python
# coding: utf-8

# # Comments

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# This is a comment. It will not run


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1 # This is a comment in the middle of code. It will not run


# # Types

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# If you put something at the end of a code block, Jupyter will print it
1


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# Using the "type" keyword will tell you the type of something
type(1)


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# Integers are not the same as floats!
type(1.)


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# There are multiple ways to declare floats
type(1.0)


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# Here is an example of a boolean
type(True)


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# This is the other boolean
type(False)


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# Here is an example of a string
type('Hello world!')


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# Here is an example of a list
type([0, 1, 2])


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# Here is an example of a NoneType
type(None)


# # Variable assignments

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# Python variables are not math variables.
# They can be assigned and hold a value
x = 1
# Putting a variable at the end of a code block will print it
x


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# You can find the type of what the variable holds by using type
type(x)


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# Variables can be reassigned
x = 2
x


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# The name of a variable is not related to the content at all
two = 2
two


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# As you can see, the variable "two" holds 3
two = 3
two


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# Variables are case-sensitive
X = 4.


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X


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x


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# Variables are case-senstive for any part of the variable
Xyz = 3
Xyz


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xyz = 4
xyz


# # Operations (integral types)

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# Python things can be combined using arithmetic operators
1 + 1


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# The result of arithmetic operations can be assigned to variables
x = 10. - 5.3
x


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# The result of an arithmetic operation WILL NOT CHANGE the variable contents
x * 2


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# as you can see here
x


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x = x * 2
x


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# An example of floating point division
4.0 / 2.0


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# An example of division of integers
4 / 3


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# An example of integer division, that returns ONLY the integral part
4 // 3


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# Can you guess the output?
7 // 3


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# How about now?
10 // 3


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4.0 // 3.0


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# An example of "modulus" or "mod" or "finding the remainder"
4 % 3


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# What is the answer?
7 % 3


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# How about now?
10 % 4


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# How about now?
10 % 2


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# And now?
143 % 5


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x = 1
x = x + 1
x


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x = 1
x += 1 # This is equivalent to "x = x + 1"
x


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x = 10
x -= 5
x


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x = 60
x *= 50
x


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x = 100
x /= 10
x


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x = 100
x //= 10
x


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x = 10
y = 10
x == y


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x = 10
y = 20
x == y


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# Order of operations matters!
# *, /, % happen first, in the order they appear
1 + 3 * 20 % 7


# # Operations (boolean types)

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# Booleans can be combined using logical ands
# The result of logical and is True if and only if both sides are True
True and False


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# Booleans can be combined using logical ors
# The result of logical or is True if either side is True
True or False


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# You can put operations that result in booleans and combine them
(1 == 1) and (2 == 2)


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# Logical negation changes True to False
not True


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# and False to True
not False


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not (1 == 1)


# # Operations (string, list)

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# Adding strings is called "concatenation"
'Hello' + ' ' + 'world!'


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# Aside: can you have a 1-element list?
[0]


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# Aside: can you have a 0-element list?
[]


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# Adding list is also called "concatenation"
[0] + [1]


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x = [0]
y = [1]
x + y


# # Errors

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# Errors occur when something you do that isn't allowed
# Remember: True is supposed to be capitalized!
true


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# Variables must be assigned before being used
abcd


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# Once you assign a variable you can use it
abcd = 1


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abcd


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# Dividing by 0 is undefined and thus an error in Python
1 / 0


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