A Crash Course In Python And Manipulation of Data

My objective for this lesson is to make you aware of python and its usefulness in wrangling with data.

We are going to start slow with data types and expressions. Eventually, by the end of the lesson, we will programmatically genrerate data and then use a sophisticated library to help us manage and visualize it all.

Data Types

Numbers



In [4]:

    
1









    Out[4]:





1



In [5]:

    
2 + 4









    Out[5]:





6



In [7]:

    
2 - 3









    Out[7]:





-1



In [8]:

    
100 *  5









    Out[8]:





500



In [9]:

    
4 / 2









    Out[9]:





2.0



In [10]:

    
4 / 3









    Out[10]:





1.3333333333333333



In [11]:

    
4 % 3









    Out[11]:





1



In [14]:

    
type(3)









    Out[14]:





int



In [15]:

    
type(3.5)









    Out[15]:





float

Strings



In [16]:

    
"Cats"









    Out[16]:





'Cats'



In [17]:

    
'Dogs'









    Out[17]:





'Dogs'



In [18]:

    
'Hello World'









    Out[18]:





'Hello World'



In [19]:

    
"I can't wait to program for the rest of my life"









    Out[19]:





"I can't wait to program for the rest of my life"



In [46]:

    
"My name is " + "Andre"









    Out[46]:





'My name is Andre'



In [20]:

    
type("Cats")









    Out[20]:





str



In [21]:

    
type("Doge")









    Out[21]:





str

Arrays



In [23]:

    
[1, 2, 3]









    Out[23]:





[1, 2, 3]



In [25]:

    
[100, 4, 12, 45]









    Out[25]:





[100, 4, 12, 45]



In [26]:

    
["Cat", "Dog", "Zebra"]









    Out[26]:





['Cat', 'Dog', 'Zebra']

Variables

variable_name_here = expression_here



In [5]:

    
x = 4



In [6]:

    
x









    Out[6]:





4



In [2]:

    
x + 2









    Out[2]:





6



In [3]:

    
my_sweet_ride = "ferrari"



In [4]:

    
my_sweet_ride









    Out[4]:





'ferrari'



In [47]:

    
my_name = "Andre"
"My name is " + my_name









    Out[47]:





'My name is Andre'



In [7]:

    
type(x)









    Out[7]:





int



In [8]:

    
type(my_sweet_ride)









    Out[8]:





str



In [9]:

    
x = 4
y = 100
z = x * y



In [10]:

    
z









    Out[10]:





400



In [14]:

    
my_array = [100, 67, 4, 101]



In [16]:

    
my_array[0]









    Out[16]:





100



In [17]:

    
my_array[1]









    Out[17]:





67



In [18]:

    
my_array[2]









    Out[18]:





4



In [22]:

    
# This will error out because the index is asking for a location that is not in the
# array (out of range).
my_array[4]









    



---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-22-e59fad3b875c> in <module>()
      1 # This will error out because the index is asking for a location that is not in the erray (out of range)
----> 2 my_array[4]

IndexError: list index out of range



In [23]:

    
# Access an index using a var!
pointless_var = 2
my_array[pointless_var]









    Out[23]:





4



In [33]:

    
my_array[0:3]









    Out[33]:





[100, 67, 4]



In [30]:

    
string_1 = "We are so lame."
string_1[0]









    Out[30]:





'W'



In [31]:

    
string_1[0:10]









    Out[31]:





'We are so '



In [32]:

    
new_string = string_1[0:10] + "cool."
new_string









    Out[32]:





'We are so cool.'

There are many ways to change the contents of lists besides assigning new values to individual elements:



In [19]:

    
odds = [1, 3, 5, 7]
print('odds are:', odds)









    



odds are: [1, 3, 5, 7]



In [20]:

    
odds.append(11)
print('odds after adding a value:', odds)









    



odds after adding a value: [1, 3, 5, 7, 11]



In [21]:

    
del(odds[0])
print('odds after removing the first element:', odds)









    



odds after removing the first element: [3, 5, 7, 11]



In [22]:

    
odds.reverse()
print('odds after reversing:', odds)









    



odds after reversing: [11, 7, 5, 3]



In [24]:

    
odds = [1, 3, 5, 7]
print('odds are:', odds)
odds = odds + [11]
print('odds are:', odds)









    



odds are: [1, 3, 5, 7]
odds are: [1, 3, 5, 7, 11]

Dictionaries



In [35]:

    
first_dict = {}



In [36]:

    
first_dict









    Out[36]:





{}



In [37]:

    
first_dict["x"] = "some_var"



In [38]:

    
first_dict









    Out[38]:





{'x': 'some_var'}



In [40]:

    
first_dict[x] = 4



In [41]:

    
first_dict









    Out[41]:





{4: 4, 'x': 'some_var'}



In [42]:

    
second_dict = {"key_value": "value", "second_key_value": "second_value"}



In [43]:

    
second_dict









    Out[43]:





{'key_value': 'value', 'second_key_value': 'second_value'}



In [44]:

    
second_dict["key_value"]









    Out[44]:





'value'



In [45]:

    
second_dict["second_key_value"]









    Out[45]:





'second_value'

Exercise Block #1

Create two python variables that will add up to 100.



In [ ]:

Add two python strings together to create a sentence.



In [ ]:

Create an array with number values only and assign it to a variable name. Then access the first element of that array.



In [ ]:

Create a dictionary and access a few values from it



In [ ]:

Boolean Logic



In [49]:

    
True









    Out[49]:





True



In [50]:

    
False









    Out[50]:





False



In [51]:

    
1 == 1









    Out[51]:





True



In [52]:

    
2 == 1









    Out[52]:





False



In [53]:

    
1 < 10









    Out[53]:





True



In [54]:

    
1 <= 10









    Out[54]:





True



In [55]:

    
1 > 10









    Out[55]:





False



In [56]:

    
1 >= 10









    Out[56]:





False



In [57]:

    
"dogs are better than cats" == "dogs are better than cats"









    Out[57]:





True



In [59]:

    
"dogs" == "cats"









    Out[59]:





False



In [60]:

    
"abc" < "def"









    Out[60]:





True



In [61]:

    
"abc" > "def"









    Out[61]:





False



In [62]:

    
"a" < "b"









    Out[62]:





True



In [63]:

    
"a" > "b"









    Out[63]:





False

Logic Flow



In [5]:

    
x = 5

if x < 10:
    print("This workshop is okay")









    



This workshop is okay



In [6]:

    
x = 11

if x < 10:
    print("This workshop is okay")
else:
    print("This workshop is lame")









    



This workshop is lame



In [7]:

    
str_1 = "Andre"

if str_1 == "Andre":
    print("Welcome to the danger zone")









    



Welcome to the danger zone



In [12]:

    
my_var = 50

if my_var > 100:
    print("Large value")
    y = 10  # Example of doing different types of expressions and statements
elif my_var > 10:
    print("Medium value")
    y = 5
else:
    print("Small value")
    y = 0









    



Medium value

Looping



In [14]:

    
list_of_elements = [1, 2, 3, 4]
# This could take a while to add everything by hand.

# This could take a while to add everything by hand.
for value in range(0, 10):
    print(value)



In [15]:

    
total_sum = 0
for value in range(0, 10):
    total_sum = total_sum + value
total_sum









    Out[15]:





45



In [16]:

    
list_of_elements = []
for value in range(0, 10):
    list_of_elements.append(value)
list_of_elements









    Out[16]:





[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]



In [17]:

    
# We can also start looping through all these values
for new_value in list_of_elements:
    print(new_value * 2)



In [18]:

    
word = 'lead'
for char in word:
    print(char)









    



l
e
a
d

For loops take the form of

for variable in collection:
    do things with variable

Exercise Block #2

Use a for-loop to convert the string “hello” into a list of letters:

["h", "e", "l", "l", "o"]

Hint: You can create an empty list like this:

my_list = []



In [ ]: