Introduction to Python and Jupyter Notebook

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print("Hello World!")


    

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# We can write comments like this.
print("Hello World!") # Or here. You can write anything you want.

# It's a good way of describing what your code does.


    

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# Note: we can't use upper case. We will get a "NameError".
PRINT("Hello World!")


    

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# Get help with a command by putting ? in front of it.
?print


    

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# Run file on your computer.
%run 00-hello-world.py


    

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%%time 
# How long does the code take to execute? Put %%time at the top to find out.
# Loop 10 million times.
for i in range(10000000):
    pass


    

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10 + 5


    

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Name = "John Doe"              # String.
Age = 40                       # Integer.
Height = 180.3                 # Float.
Married = True                 # Boolean (True/False).
Children = ["Emma", "Thomas"]  # List.


    

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# Print the contents of variable.
Age


    

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# Print many at the same time.
print(Name)
print(Age)
print(Height)
print(Married)
print(Children)


    

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# Change the value.
Age = Age + 10
print(Age)


    

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# We can't add numbers to strings. We will get a "TypeError".
Name + Age


    

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# We need to convert age to string.
mytext = Name + str(Age)
print(mytext)


    

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text = "The quick brown fox jumps over the lazy dog"


    

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# Get single characters from the text string.
print(text[0])  # Get the first character
print(text[4])  # Get the fifth character


    

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# Show the characters between 4th and 9th position (the word "quick").
print(text[4:9])


    

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# Replace "dog" with "journalist.
text.replace("dog", "journalist")


    

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# Make the text upper case, lower case, or title case.
print(text.upper())
print(text.lower())
print(text.title())


    

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# Get the length of the text string.
len(text)


    

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# Find where the position where "dog" starts.
print(text.find("dog"))

# If we search for something that is not in the text string, -1 will be returned.
print(text.find("candy"))


    

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# Lets combine many things!

# First, we save the text to a new variable so we can keep the old.
newtext = text

# Then, we do a lot of replacements.
newtext = newtext.replace("quick", "depressed")
newtext = newtext.replace("fox", "elephant")
newtext = newtext.replace("lazy", "even more depressed")
newtext = newtext.replace("dog", "journalist")

# After that, we title case it to make it look prettier.
newtext = newtext.title()

print(newtext)


    

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# First, we assign a value to the variable "Name" and "Age".
Name = "John Doe"
Age = 40

# Check if age equals 40.
if Age == 40:
    print(Name + " is 40 years old.")
else:
    print(Name + " is not 40 years old.")


    

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# Lets change the age.
Age = 24

# Check many things at once: Is 40 years old? If not, is he above 40? If not,
# is he above 20 and below 40? If we can't find any match, run the code under "else".
if Age == 40:
    print(Name + " is 40 years old.")
elif Age > 40:
    print(Name + " is above 40 years old.")
elif Age > 20 and Age < 40:
    print(Name + " is above 20 and below 40.")
else:
    print(Name + " is 20 years or younger.")


    

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# Loop 5 times.
for i in range(5):
    print(i)


    

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# Loop from 0 to 100, by ever 25.
for i in range(0, 100, 25):
    print(i)


    

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# We can use for loops on lists.
Children = ["Emma", "Thomas", "Nicole"]    # Make a list with 3 text strings.

for child in Children:
    print(child)


    

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# We can use for loops on numbers.
YearsOld = [14, 5, 4]    # Make a list with 3 numbers.

for age in YearsOld:
    print(age)


    

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# A function that we name "calc" that multiples two numbers together. 
# It takes to variables as input (x and y).
# The function then returns the results of the multiplication.
def calc(x, y):
    return(x * y)


    

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# Now we just use the name of the function.
calc(10, 5)


    

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# Long list with names.
names = ["Adelia", "Agustin", "Ahmed", "Alethea", "Aline", "Alton", "Annett", "Arielle", "Billie", 
         "Blake", "Brianne", "Bronwyn", "Charlesetta", "Cleopatra", "Colene", "Corina", "Cruz", 
         "Curt", "Dawn", "Delisa", "Dolores", "Doloris", "Dominic", "Donetta", "Dusti", "Edna", 
         "Eliana", "Elna", "Emma", "Eugenio", "Francie", "Francisca", "Georgeanna", "Gerald", 
         "Gerry", "Gisele", "Hee", "Heidy", "Howard", "Iris", "Irving", "Izola", "Ja", "Jacinta", 
         "Jamey", "Jana", "Jeanie", "Jeffry", "Joeann", "Jonna", "Juliann", "Kacey", "Kandra", 
         "Karissa", "Kecia", "Kisha", "Leila", "Leslee", "Lisbeth", "Lizzette", "Lorie", "Luanna", 
         "Lynelle", "Lynna", "Lynnette", "Maire", "Maricela", "Mario", "Marsha", "Maxwell", 
         "Meggan", "Miquel", "Mireya", "Nakisha", "Natacha", "Nathanial", "Niesha", "Norberto", 
         "Norene", "Patrick", "Phoebe", "Phylicia", "Rashad", "Reatha", "Rebecka", "Renate", "Riley", 
         "Rochel", "Sadie", "Shawanna", "Sherri", "Sunshine", "Tamala", "Tish", "Vincent", "Yun"]


    

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# Create a variable that counts the number of names.
count = 0

for current_name in names:         # For loop that goes through each name in the list "names".
    if current_name[0] == "E":     # Is the first character the letter E?
        count = count + 1          # Add 1 to the variable "counter".

print("There are " + str(count) + " names that starts with the letter 'E'.")


    

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# Lets create a function so we can reuse the code.
# The function takes to inputs (names and letters),
# which is a list of names and the letter we want to look for.
def countnames(names, letter):
    count = 0                          # Create a variable that counts the number of names.
    for current_name in names:         # For loop that goes through each name in the list "names".
        if current_name[0] == letter:  # Is the first character the letter stored in the variable "letter"?
            count = count + 1          # Add 1 to the variable "counter".
    return(count)                      # At last, we return the counter.

# Call the functions with different letters (and save the results to variables).
e = countnames(names, "E")
f = countnames(names, "F")
p = countnames(names, "P")

# Print the results.
print("There are " + str(e) + " names that starts with the letter 'E'.")
print("There are " + str(f) + " names that starts with the letter 'F'.")
print("There are " + str(p) + " names that starts with the letter 'P'.")