Untitled
A look at for loops over various types of containersunknown
python
a year ago
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# WEBINAR: For Loops
# We use loops to repeat actions
# a WHILE loop... is an IF that repeats as long as the loop condition remains True
# FOR LOOPS are used for repeating actions for every element in a container
# (list, dict, str, tuple, etc)
# Basic syntax of a for loop
# for ___ in _someContainer_:
# For Loop variables (the word after the for keyword) are SPECIAL VARIABLES
# that come along with this loop
# LIST
myList = ["Agent Scully", "Agent Mulder", "Walter Skinner", "CSM", "Mr. X"]
# for item in myList:
# print(item)
#
# # TUPLE
# myTuple = ("Gilligan", "Castaway002", "red", "crew")
# for item in myTuple:
# print(item)
#
# # STRING
# myStr = "It was the best of times."
# for char in myStr:
# print(char)
# LOOP A NUMBER OF TIMES
# RANGE OBJECT... range()
# range(start=0, stop, step=1)
# range(5) --> range(0, 5, 1) ----> [0, 1, 2, 3, 4]
# for num in range(0, 5, 1):
# print(num)
# Looping over an indexed container, and I need to know the INDEX
# 2 choices... range() of len(), enumerate()
# RANGE of LEN
# for i in range(0, len(myList), 1):
# # print(i)
# # print(myList[i])
# print(f"{i}: {myList[i]}")
#
# # ENUMERATE
# for i, item in enumerate(myList):
# print(f"{i}--> {item}")
# What index is this value at in the list?
# print(myList.index("Mr. X"))
# DICT
# myDict = {
# key: value,
# key: value
# }
# myDict["someKey"] # retrieve the value associated with the key "someKey"
# myDict["someKey"] = "someVal" # assigns value to key
bestOfXF = {
"1x00": "Pilot",
"2x10": "Red Museum",
"2x14": "Die Hand Die Verletzt",
"2x20": "Humbug",
"3x04": "Clyde Bruckman's Final Repose",
"3x12": "War of the Coprophages",
"3x20": "Jose Chung's From Outer Space",
"4x05": "The Field Where I Died",
"5x05": "The Post Modern Prometheus",
"5x17": "All Souls"
}
for key in bestOfXF:
# print(key)
# print(bestOfXF[key])
# "Check out Episode ___ or '---'."
print(f"Check out Episode {key} or '{bestOfXF[key]}'.")
# EXTRA... this is a general pattern you'll use a lot with all types of containers
# FILL THE BASKET / FILTER
agentList = [] # start the new container, empty, before the loop
for item in myList:
# filter with an if
if "Agent" in item:
agentList.append(item)
print(agentList)
season2 = {}
for k in bestOfXF:
if "2x" in k:
season2[k] = bestOfXF[k]
print(season2)
# math questions in a range
# How many numbers 0-100 are evenly divisible by 25?
numList = []
for num in range(0, 101):
if num % 25 == 0:
numList.append(num)
print(len(numList))
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