# log from lecture 1, 2/13/17, DS
Python 3.5.2 |Continuum Analytics, Inc.| (default, Jul 5 2016, 11:41:13) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
# I'll use comments (lines starting with '#') to provide a few explanations
# basic math
>>> 2+3
5
>>> 1+1+1
3
>>> 1 + 1 + 1
3
>>> 2 + 3 * 4
14
>>> (2 + 3) * 4
20
>>> 3 * -4
-12
>>> 20 / 4
5.0
>>> 10 / 4
2.5
>>> 10 // 4 # integer division (a comment!)
2
>>> 97 // 10
9
>>> 97 % 10 # remainder
7
>>> 97 / 10
9.7
>>> -97 / 10
-9.7
>>> -97 // 10
-10
>>> 8 ** 2
64
>>> 81 ** 0.5
9.0
>>> float(2)
2.0
>>> int(2.9)
2
# assigning a value to a variable:
>>> x = 2
>>> x
2
>>> 2 = x # this won't work -- the variable has to be on the left
File "", line 1
SyntaxError: can't assign to literal
>>> x = 5 # you can re-assign, which overwrites the old value
>>> x
5
# bbq party
# - you're having a party and you're trying to figure out how many hot dogs to buy. Here's what you know:
# - tim isn't a big fan of hot dogs, so he'll only eat 1
# - amy generally eats 2
# - todd always eats twice as many as amy
# - brenda eats one less than todd
# - mark eats half as many as brenda, but likes to take an extra on his way home
>>> tim = 1
>>> amy = 2
>>> todd = 2 * amy
>>> brenda = todd - 1
>>> brenda
3
>>> mark = brenda / 2 # this is 1.5, but need whole hot dogs
>>> mark = brenda // 2 # rounds down instead of up...
>>> mark = (brenda + 1) // 2 # but this rounds up!
>>> mark = (brenda + 1) // 2 + 1 # remember, one more for the way home
>>> total_hotdogs = tim + amy + todd + brenda + mark
>>> total_hotdogs
13
>>> runfile('C:/Users/schar/Desktop/cs150/bbq.py', wdir='C:/Users/schar/Desktop/cs150')
>>> brenda
3
>>> brenda // 2
1
>>> brenda / 2
1.5
>>> (brenda + 1)// 2
2
>>> runfile('C:/Users/schar/Desktop/cs150/bbq.py', wdir='C:/Users/schar/Desktop/cs150')
13
>>>