In [3]:

    

example_variable = "ljhkjhkjkgjkg"
# I can display what is inside example_variable by using 
# the print command lets us do this
# try changing the value.  
print (example_variable)


    

    




ljhkjhkjkgjkg

In [27]:

    

# STRINGS are one or more characters stung togehter: "Hello World!"
greeting = "Hello World!"
print ("The greeting is, %s" % greeting)


    

    




The greeting is, Hello World!

In [3]:

    

# LISTS are collections of things in a list: 

list_of_characters  = ['a', 'b', 'c'] 
print (list_of_characters)

list_of_numbers = [1, 2, 3, 4]
print (list_of_numbers )

# We can access any value in the list by it's position in the list.  This is called the index
# Indexes start at 0
print ("The second value in the list is %d" % list_of_numbers[1])


    

    




['a', 'b', 'c']
[1, 2, 3, 4]
The second value in the list is 2

In [23]:

    

# DICTIONARIES are collections of things that you can lookup like in a real dictionary:
dictionary_of_definitions = {"aardvark" : "The aardvark is a medium-sized, burrowing, nocturnal mammal native to Africa.",
                             "boat" : "A boat is a thing that floats on water"}

# we can find the definition of aardvark by giving the dictionary the "key" to the definition we want.
# In this case the key is the word we want to lookup
print ("The definition of aardvark is, %s" % dictionary_of_definitions["aardvark"]) 

dictionary_of_colors = {1 : "purple", 2 : "green", 3 : "blue"}
# This sets up an association between numbers and colors.  You can do this for any pair or pairs of associations
# Sometimes dictionaries are called "associative arrays" for this reason.
# We call each association a "key-value pair".  
# A dicitonary can be thought of as a list of associations known as key-value pairs

# we can find the color associated with a number by asking the dictionary the number we want to lookup
print ("The color at item 2 is %s " % dictionary_of_colors[2])

#


    

    




The definition of aardvark is, The aardvark is a medium-sized, burrowing, nocturnal mammal native to Africa.
The color at item 2 is green 

In [3]:

    

# TUPLES are like sets of values
# an example is a set of x and y coordinates like this
tuple_of_x_y_coordinates = (3, 4)
print (tuple_of_x_y_coordinates)

# tuples can have any number of values
coordinates = (1, 7, 38, 9, 0)
print (coordinates)
icecream_flavors = ("strawberry", "vanilla", "chocolate")
print (icecream_flavors)

# you might be asking, what is the difference between a tuple and a list
# Once you have created a list you can add more items to it
# Once you have created a tuple, you cannot add more items to it

# Let's start with an empty list
add_things_list = []
add_things_list.append("one")
print (add_things_list)
add_things_list.append("two")
print (add_things_list)


    

    




(3, 4)
(1, 7, 38, 9, 0)
('strawberry', 'vanilla', 'chocolate')
['one']
['one', 'two']

In [ ]:

    

# Add things to the list above:  add_things_list


    

In [13]:

    

# Conditionals are how we make a decision in the program
# we do this with something called an "if statement"
# Here is an example

it_is_daytime = False # this is the variable that holds the current condition of it_is_daytime which is True or False 

if it_is_daytime:
    print ("Have a nice day.")
else:
    print ("Have a nice night.")
    
# before running this cell
# what will happen if we change it_is_daytime to True?
# what will happen if we change it_is_daytime to False?


    

    




Have a nice night.

In [18]:

    

# what if a condition has more than two choices? Does it have to use a boolean?
# python if-statments will let you do that with elif
# elif stands for "else if"
user_name = "Joe"

if user_name == "Marnee":  #notice the double equals sign.  This is used to differentiate between comparing two values and
                            # and assiging a value to a variable
    print ("Marnee likes to program in Python and F#")
elif user_name == "Frank":
    print ("Frank does lots of interesting image processing in Python.")
elif user_name == "Julian":
    print ("Julian ia an awesome programmer at Cyverse")
else:
    print ("We do not know who you are")
    
# for each possibility of user_name we have an if or else-if statment to check the value of the name
# and print a message accordingly.


    

    




We do not know who you are

In [19]:

    

# loops tell a program to do the same thing over and over again until a certain condition is met
# we can loop over cellections of things like lists or dictionaries
# or we can create a looping structure


    

In [23]:

    

# LOOPING over a collection
# LIST

# If I want to print a list of fruits, I could write out each print statment like this:
print("apple")
print("banana")
print("mango")

# or I could create a list of fruit
# loop over the list
# and print each item in the list
list_of_fruit = ["apple", "banana", "mango"]

# this is how we write the loop
# "fruit" here is a variable that will hold each item in the list, the fruit, as we loop
# over the items in the list
print (">>looping>>")
for fruit in list_of_fruit:
    print (fruit)


    

    




apple
banana
mango
>>looping>>
apple
banana
mango

In [36]:

    

# LOOPING over a collection
# DICTIONARY

# We can do the same thing with a dictionary and each association in the dictionary

fruit_price = {"apple" : 0.10, "banana" : 0.50, "mango" : 0.75}
for key, value in fruit_price.items():
    print ("%s price is %f" % (key, value))


    

    




apple price is 0.100000
banana price is 0.500000
mango price is 0.750000

In [7]:

    

# LOOPING a set number of times
# We can do this with range 
# range automatically creates a list of numbers in a range
# here we have a list of 10 numbers starting with 0 and increasing by one until we have 10 numbers
# What will be printed
for x in range(0,10):
    print (x)


    

    




0
1
2
3
4
5
6
7
8
9

In [ ]:

    

# That's it.  With just these data types, structures, and logic, you can build a program
# let's do that next with functions