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

# ## Basic Training
# 
# UC Berkeley Python Bootcamp
# <pre>
# 
# 
# </pre>
# follow along the code at: 
# http://bit.ly/pyboot_01
# 

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get_ipython().run_line_magic('run', 'talktools.py')


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from IPython.display import YouTubeVideo
YouTubeVideo("imhrDrE4-mI",width="640",height="390")


# ### Outline
# 
#  - Hello World!
#  - calculator/basic math
#  - strings
#  - variables
#  - basic control statements
#  -   indentation!

# <img src="https://raw.github.com/profjsb/python-bootcamp/master/Lectures/01_BasicTraining/day_1_basic_training_slide1.png">

# <img src="https://raw.github.com/profjsb/python-bootcamp/master/Lectures/01_BasicTraining/day_1_basic_training_slide2.png">

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print("Hello, world.")


# # Calculator #
# 
# > there are `int` and `float` (but not doubles)

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print(2 + 2)


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2 + 2 


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print(2.1 + 2)


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2.1 + 2 == 4.0999999999999996


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get_ipython().run_line_magic('run', 'talktools')


#   - Python stores floats as their byte representation so is limited by the same 16-bit precision issues as most other languages
# 
#   - In doing calculations, unless you specify otherwise, Python will store the results in the smallest-byte representation

# > 1. Indentation matters!
# > 2. When you mess up, Python is gentle
# > 3. \# starts a comments (until the end of the line)

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print(2 + 2)
  2 + 2


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2 # this is a comment and is not printed


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# this is also a comment


#  &nbsp;

# ** Calculator **
# 
#   - all the math operators you'd expect, including `**` for power.
#   - In Python 3, there is no distinction between `int` and `long`
# 

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42**42


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(42**42).bit_length()


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bin(42**42)


# Division always leads to a float

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2 / 2


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2 / 2.0


# Note: This is an important difference between Python 2 and Python 3. Old-style division between `int`s can be done with a double slash `//`

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2 // 2


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3 // 2


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2.5 // 2 # egad, dont do this.


# There is also `complex` types

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complex(1,2)


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1+2j


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1 + 2j - 2j


# Note: Access to [`decimal`](https://docs.python.org/3/library/decimal.html#module-decimal) (decimal fixed point and floating point arithmetic) and [`fraction`](https://docs.python.org/3/library/fractions.html#module-fractions) types/operations is through built-in `modules`.

#  &nbsp;

# ## Let's do some math

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(3.0*10.0 - 25.0)/5.0


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print(3.085e18*1e6)  # this is a Megaparsec in units of cm!


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t = 1.0      # declare a variable t (time)
accel = 9.8  # acceleration in units of m/s^2


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# distance travelled in time t seconds is 1/2 a*t**2
dist = 0.5*accel*t*t
print(dist) # this is the distance in meters


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dist1 = accel*(t**2)/2
print(dist1)


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dist2 = 0.5*accel*pow(t,2)
print(dist2)


#    - **variables** are assigned on the fly
#    - multiplication, division, exponents as you expect

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print(6 / 5) ; print(9 / 5)


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print(6 // 5) ; print(9 // 5) # remember double-slash integer division returns the floor


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6 % 5  # mod operator, get the remainder. x = (x // y)*y + x % y


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1 << 2 ## shift: move the number 1 by two bits to the left
       ##        that is make a new number 100 (base 2)


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5 >> 1 ## shift: move the number 5 = 101 (base 2) one to
           ## to the right (10 = 2)


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x = 2 ; y = 3  ## assign two variables on the same line!
x | y          ## bitwise OR


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x ^ y          ## exclusive OR (10 ^ 11 = 01)


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x & y          ## bitwise AND


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x = x ^ y ; print(x)


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x += 3 ; print(x)


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x /= 2.0 ; print(x)


# we'll see a lot more mathy operators and functions later

# ## Relationships ##

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# from before dist1  = 4.9 and dist = 4.9
dist1 == dist


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dist < 10


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dist <= 4.9


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dist < (10 + 2j)


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dist < -2.0


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dist != 3.1415


# Try using some Greek characters as variables:
# 
#   \Delta <tab>

#  &nbsp;

# ** More on Variables & Types **

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0 == False


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not False


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0.0 == False


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not (10.0 - 10.0)


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not -1


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not 3.1415


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x = None    # None is something special. Not true or false
None == False


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None == True


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False or True


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False and True


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float("nan") == True


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print(float('inf'))


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import math
math.isnan(float("NaN"))


#  &nbsp;

# ** More on Variables & Types **

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print(type(1))


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x = 2 ; type(x)


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# bytes are immutable sequences of numbers from 0-255
print((255).to_bytes(2,byteorder='big')) ; type(bytes(10))


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type(2) == type(1)


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print(type(True))


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print(type(type(1)))


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print(type(pow))


#  &nbsp;

# we can test whether something is a certain type with **`isinstance()`**

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isinstance(1,int)


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isinstance(1,(int,float))


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isinstance("spam",str)


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isinstance(1.212,int)


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isinstance(1.212,int)


# We'll see later than numbers are objects, which have functions (`methods`) that can act upon themselves:

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(1.212).is_integer()


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(1.0).is_integer()


# builtin-types: **`int`**, **`bool`**, **`str`**, **`float`**, **`complex`**, **`bytes`**

# # Strings

# Strings are a sequence of characters
# - they can be indexed and sliced up as if they were an array
# - you can glue strings together with + signs
# 
# Strings are **immutable** (unlike in C), so you cannot change a string in place (this isn't so bad...)
# 
# Strings can be formatted and compared 

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x = "spam" ; print(type(x))


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print("hello!\n...my sire.")


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"hello!\n...my sire."


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"wah?!" == 'wah?!'


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print("'wah?!' said the student")


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print("\"wah?!\" said the student")


# backslashes (\\) start special (escape) characters:
# ```
#      \n   = newline  (\r = return)
#      \t   = tab
#      \a   = bell
# ```
# string literals are defined with double quotes or quotes.
# The outermost quote type cannot be used inside the string (unless it's escaped with a backslash)
# 
# See: http://docs.python.org/reference/lexical_analysis.html#string-literals

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print("\a\a\a")  # try this in CLI python, not the notebook


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# raw strings don't escape characters
print(r'This is a raw string...newlines \r\n are ignored.')


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# Triple quotes are real useful for multiple line strings
y = '''For score and seven minutes ago,
    you folks all learned some basic mathy stuff with Python
    and boy were you blown away!'''
print(y)


# 
#   - prepending ``r`` makes that string "raw"
# 
#   - triple quotes allow you to compose long strings
#   
#   https://docs.python.org/3.4/reference/lexical_analysis.html#literals

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print("\N{RIGHT CURLY BRACKET}")


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print("\N{BLACK HEART SUIT}")


# http://www.fileformat.info/info/unicode/char/search.htm

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s = "spam" ; e = "eggs"
print(s + e)


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print("spam"
      "eggs"
      "Trumpkins")


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print(s
      "eggs")


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print(s + " and " + e)


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print(s,"and",e, sep=" ")


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print("green " + e + " and\n " + s + "\n\t ... and Trumpkins")


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print(s*3 + e)


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print(s*3,e,sep="->")


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print("*"*50)


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print("spam" == "good") ; print("spam" == "spam")


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"spam" < "zoo"


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"s" < "spam"


#  - you can concatenate strings with ``+`` sign
#  - you can do multiple concatenations with the ``*`` sign
#  - strings can be compared

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print('I want' + 3 + ' eggs and no ' + s)


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print('I want ' + str(3) + ' eggs and no ' + s) 


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pi = 3.14159
print('I want ' + str(pi) + ' eggs and no ' + s)


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print(str(True) + ":" + ' I want ' + str(pi) + ' eggs and no ' + s)


# you must concatenate only strings, coercing ("casting") 
# other variable types to `str`

# there's a cleaner way to do this, with string formatting. we'll see that tomorrow.

# ### Getting input from the user: always a string response

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faren = input("Enter the temperature (in Fahrenheit): ")


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cent = (5.0/9.0)*(faren - 32.0)


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faren = float(faren)
cent = (5.0/9.0)*(faren - 32.0) ; print(cent)


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faren = float(input("Enter the temperature (in Fahrenheit): "))
print((5.0/9.0)*(faren - 32.0))


#  &nbsp;

# #### We can think of strings as arrays (although, unlike in C you never really need to deal with directly addressing character locations in memory)

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s ="spam"
len(s)


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len("eggs\n")


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len("")


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s[0]


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s[-1]


#  - ``len()`` gives us the length of an array
#  - strings are zero indexed
#  - can also count backwards

# We can think of strings as arrays
# (although, unlike in C you never really need to deal with directly addressing character locations in memory)

# <img src="https://raw.github.com/profjsb/python-bootcamp/master/Lectures/01_BasicTraining/spam.png">

# useful for slicing: indices are between the characters

# <img src="https://raw.github.com/profjsb/python-bootcamp/master/Lectures/01_BasicTraining/spam.png">

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s[0:1]  # get every character between 0 and 1


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s[1:4]  # get every character between 1 and 4 


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s[-2:-1] 


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## slicing [m:n] will return abs(n-m) characters
s[0:100] # if the index is beyond the len(str), you dont segfault!


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s[100]


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s[1:]  # python runs the index to the end


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s[:2]  # python runs the index to the beginning


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s[::-1] # print it out backwards


#     s = s[:n] + s[n:] for all n

# ## Basic Control (Flow)

# Python has pretty much all of what you use:
# 
#     if...elif...else,  for,  while
# 
# As well as:
# 
#     break, continue (within loops)
#     
# Does not have:
# 
#     case (explicitly), goto
# 
# Does have:  `pass`

# ### Flow is done within blocks (where indentation matters)

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x = 1
if x > 0:
    print("yo")
else:
    print("dude")


# Note: if you are doing this within the Python interpreter you'll see the ...
# ```
# >>> x = 1
# >>> if x > 0:
# ...     print "yo"
# ... else:
# ...     print "dude"
# ... 
# yo
# ```

# Note colons & indentations (tabbed or spaced)

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x = 1
if x > 0:
      print("yo")
else:
           print("dude")


# Indentations with the same block must be the same but not within different blocks (though this is ugly)

# one-liners

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print("yo" if x > 0 else "dude")


# a small program... Do Control-C to stop (in Python/IPython) or "Kernel->Interrupt" in IPython notebook

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x = 1
y = 0
while True:
    print("yo" if x > 0 else "dude")
    x *= -1
    y += 1
    if y > 42:
        break


# case statements can be constructed with 
# just a bunch of if, elif,...else

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if x < 1:
     print("t")
elif x > 100:
    print("yo")
else:
    print("dude")


# ordering matters. The first block of `True` in an if/elif gets executed then everything else does not.

# blocks cannot be empty

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x = "fried goldfish"
if x == "spam for dinner":
    print("I will destroy the universe")
else:
    # I'm fine with that. I'll do nothing


# `pass` is a "do nothing" statement

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if x == "spam for dinner":
    print("I will destroy the universe")
else:
    # I'm fine with that. I'll do nothing
    pass


# The double percent sign at the top of an IPython/Jupyter cell is a cell-level "magic". It's not Python itself, but defined as part of IPython/Jupyter. We'll see more on this later in the bootcamp.

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get_ipython().run_cell_magic('file', 'temp1.py', '# set some initial variables. Set the initial temperature low                                                                      \nfaren = -1000\n\n# we dont want this going on forever, let\'s make sure we cannot have too many attempts                                                                                                                           \nmax_attempts = 6\nattempt = 0\n\nwhile faren < 100:\n     # let\'s get the user to tell us what temperature it is                                                                                                                                                      \n     newfaren = float(input("Enter the temperature (in Fahrenheit): "))\n     if newfaren > faren:\n             print("It\'s getting hotter")\n     elif newfaren < faren:\n             print("It\'s getting cooler")\n     else:\n         # nothing has changed, just continue in the loop                                                                                                                                                        \n         continue\n     faren = newfaren # now set the current temp to the new temp just entered                                                                                                                                    \n     attempt += 1 # bump up the attempt number                                                                                                                                                                   \n     if attempt >= max_attempts:\n         # we have to bail out                                                                                                                                                                                   \n         break\nif attempt >= max_attempts:\n     # we bailed out because of too many attempts                                                                                                                                                                \n     print("Too many attempts at raising the temperature.")\nelse:\n     # we got here because it\'s hot                                                                                                                                                                              \n     print("it\'s hot here, people.")\n')


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get_ipython().run_line_magic('run', 'temp1')


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get_ipython().run_line_magic('run', 'temp1')


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get_ipython().run_cell_magic('file', 'temp2.py', '\n# set some initial variables. Set the initial temperature low                                                                                                                                                    \nfaren = -1000\n\n# we dont want this going on forever, let\'s make sure we cannot have too many attempts                                                                                                                           \nmax_attempts = 6\nattempt = 0\n\nwhile faren < 100 and (attempt < max_attempts):\n     # let\'s get the user to tell us what temperature it is                                                                                                                                                      \n     newfaren = float(input("Enter the temperature (in Fahrenheit): "))\n     if newfaren > faren:\n             print("It\'s getting hotter")\n     elif newfaren < faren:\n             print("It\'s getting cooler")\n     else:\n         # nothing has changed, just continue in the loop                                                                                                                                                        \n         continue\n     faren = newfaren # now set the current temp to the new temp just entered                                                                                                                                    \n     attempt += 1 # bump up the attempt number                                                                                                                                                                   \n\nif attempt >= max_attempts:\n     # we bailed out because of too many attempts                                                                                                                                                                \n     print("Too many attempts at raising the temperature.")\nelse:\n     # we got here because it\'s hot                                                                                                                                                                              \n     print("it\'s hot here, people.")\n')


# UC Berkeley Python Bootcamp - Basic Training
# (c) J. Bloom 2008-2016 All Rights Reserved

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