webinar-for-loops-2021-05-08

# WEBINAR: for loops

# FOR LOOPS are used for repeating actions for every element
# in a container like a list, string, tuple, etc...

# (as opposed to a WHILE loop, which is like an IF statement that repeats as long as it's true)

# let's get some iterable objects in here
myList = ["Gilligan", "Scooby", "Agent Scully", "Fonzie"] # tv characters
myTuple = ("Gilligan", "Castaway002", "red", "crew") # things about Gilligan

# Basic syntax of a for loop
# for __ in ___:

# Looping over a L I S T
for item in myList:        # I use "item" as my loop variable, any valid name works but keep it simple and descriptive!
    print(item) # print(item, end=" ")

# Looping over a T U P L E.. it's the same! Same with SETS too.
for item in myTuple:
    print(item)

# S T R I N G S --> each loop iteration is a single character
myString = "Just sit right back and we'll talk about Gilligan and company."
# for char in myString:     # I tend to use "char" or "ch" or "letter" when looping over a string
#     print(char, end="\n")

# D I C T I O N A R I E S
# dictionaries have KEYS and VALUES
scoobiesDCT = {
    "Scooby": "a blue collar", # key: value,
    "Shaggy": "green",
    "Velma": "orange",
    "Daphne": "purple",
    "Fred": "an ascot"
}
for key in scoobiesDCT: # for loop var for a dictionary is the KEY
    # dict[key] --> gets you the value for that key
    print(key, "always wears", scoobiesDCT[key])

# an alternate way to for loop over a dictionary
# for __, __ in dict.items()
for k, v in scoobiesDCT.items():
    print(k, "almost always wears", v)

# R A N G E
# range() function creates an iterable sequence from a number (integer)
for n in range(5):
    print(n)

# sometimes the INDEX is as important as the value at that index
for i in range(len(myList)):
    print(i, myList[i])

# or with ENUMERATE we get 2 variables
for i, item in enumerate(myList):
    # print(str(i), "-->", item)
    print("{} --> {}".format(i, item))


# some ZyBooks loop problems...

# CA 6.5.2
contact_emails = {
    'Sue Reyn' : 's.reyn@email.com',
    'Mike Filt': 'mike.filt@bmail.com',
    'Nate Arty': 'narty042@nmail.com'
}
# output for each:   s.reyn@email.com is Sue Reyn, etc
for contact in contact_emails:
    print(contact_emails[contact], "is", contact)
# or...
for key in contact_emails: # the book used "contact" as the var, I'll stick my fav "item"
    print("{} is {}".format(contact_emails[key], key))


# CA 6.10.1
user_score = 0
simon_pattern = 'RRGBRYYBGY'
user_pattern  = 'RRGBBRYBGY'
# for i in range(10):
for i in range(len(simon_pattern)):
    if simon_pattern[i] == user_pattern[i]:
        user_score += 1
    else:
        break # end loop when they no longer match
print("User score: ", user_score) # 4