webinar-python-for-loops-2022-07-16

# 2022 July 16
# WEBINAR: For Loops
# We use loops to repeat actions

# a WHILE loop... btw.. is basically an IF statement
# that repeats as long as its condition is true

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

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

myList = ["Agent Scully", "Agent Mulder", "Walter Skinner", "CSM", "Mr. X"]
for item in myList:
    print(item)

myTuple = ("Gilligan", "Castaway002", "red", "crew")
for item in myTuple:
    print(item)

myString = "It was the best of times. It was the worst of times."
# for char in myString:
#     print(char)
for char in myString:
    print(char, end="-") # end="\n"
print() # best practice... always end with a clean line, see Ch 2.9
print("Something new...")

scoobiesDCT = {
    "Scooby": "a blue collar",
    "Shaggy": "green",
    "Velma": "orange",
    "Daphne": "purple",
    "Fred": "an ascot"
}

# myDictionary[key] # retrieve the value for that key
# myDictionary[key] = value # set a new value for that key
# for ___ in scoobiesDCT: # loop var hold the KEY, whatever we name it
for key in scoobiesDCT:
    print("{} wears {}.".format(key, scoobiesDCT[key]))

for key in scoobiesDCT:
    v = scoobiesDCT[key]
    print("{} wears {}.".format(key, v))

for k, v in scoobiesDCT.items():
    print("{} still wears {}.".format(k, v))

# just looping some number of times
for n in range(5): # [0, 1, 2, 3, 4]
    print(n)

# going directly over list values
# for item in myList:

# What I'm interested in INDEX of the VALUES?
for i in range(len(myList)):
    print("{} --> {}".format(i, myList[i]))

# similar to using enumerate()
for i, item in enumerate(myList):
    print("{} ----> {}".format(i, item))


# Is a value in a container?
# You DON'T need to loop for that
# if _value_ in _container_:
print("Agent Scully" in myList)
print("Krycek" in myList)

print("Scooby" in scoobiesDCT)
print("orange" in scoobiesDCT) # values aren't checked!