webinar-python-exam-review-2022-04-30

# Exam Review 2022 Apr 30

# LABS
# Ch 3-13... all Labs!
# Ch 14-18 not as important, other than some good labs in Ch 15
# Ch 19-30 just LABS, but important practice!
# Use Submit Mode!!!

# fix your string input and output
# 1
# myVar = input().strip()
# # 2
# print("some stuff", end=" ") # if you ever override end
# print()

# see also: "I want the last one to be different"
myList = ["Agent Scully", "Agent Mulder", "Walter Skinner", "CSM", "Mr. X"]
# for item in myList:
#     print(item)
# with a loop
# for i in range(len(myList)):
#     if not i == len(myList)-1:
#         print(myList[i], end="-->")
#     else:
#         print(myList[i])
# # with string methods...
# print("-*-".join(myList))


# Comp 1: Basic syntax and knowledge: operators, data types, etc
# Comp 2: Control Flow Structures
# Basic: if statements, loops, functions
# Adv: try/except and raising errors, classes
# Comp 3: modules, working with files

# Comp 1 Basic syntax and knowledge: operators, data types, etc
# Data Types
# int
# floats
# bool (True/False)
# str
# lists
# dict
# sets # all unique values, no order/index
# tuples # immutable... return x, y --> return (x, y)

# operators
# +
# -
# *
# /
# % # modulo... What is the remainder? How many WHOLE THINGS didn't fit?
# // # floor division... x//y same as math.floor(x/y)
# ** # raise to a power... same as math.pow()
# <
# >
# <=
# >=
# = # assignment
# == # equality... asking if it's equal
# +=
# -=
# != # not equal
# # keywords
# not
# in # if _value_ in _container_, if not _value_ in _container_
# and
# or

# Comp 2 Control Flow
# IF statements... if, if/else, if/elif, if/elif/else
# LOOPS
# WHILE - basically an IF that repeats
# FOR - looping over some container, doing something a known number of times
# for __ in __:
# for item in myList:
# for i in range()
# for key in myDictionary: # myDictionary[key] # for k, v in myDictionary.items()

# FUNCTIONS
# defining/writing vs calling
# parameter vs "regular" variables
# parameters vs arguments
# return vs print() # do what the question says
# methods are functions that "belong" to that type/class
# a good function has ONE JOB, modular

# def someFunction(x, y):
#     return something
#
# if "__name__" == "__main__":
#     myInput = input()
#     # call our function
#     x = someFunction(myInput, myOtherInput)
#     print(x)

# BUILT-IN FUNCTIONS
print()
input() # input().strip(), input().rstrip()
len()
max()
min()
sum()
sorted()
reversed()
# constructor or recasting
# int() # int(input().strip())
# float() # float(input().strip())
# list()
# str()
# dict()
# set()
# tuple()
# range() # for i in range(len(someList)):
# enumerate() # for i, item in enumerate(myList):
# round() # not to be confused with math.ceil() and math.floor()
# open()
# help()
# dir() # returns a list of "attributes"
# type()

# on help() and dir():
# help() and dir()
# help(str)

# print(dir(str))
# help(str.rstrip)

# print(dir(list))
# for item in dir(list):
#     if not item.startswith("_"):
#         print(item)

# STRINGS
# be able to SLICE like it's 2nd nature
# myString = "abc"
# # myString[start:stop:step]
# # slice to reverse:  revString = myString[::-1]
# # STRING METHODS
# myString.format()
# myString.strip() # .rstrip(), lstrip()
# myString.split() # returns a list
# " ".join(listOfStrings)
# myString.replace(oldSubStr, newSubStr) # remove... myString.replace(oldSubStr, "")
# myString.count(subStr) # returns int
# myString.find(subStr) # returns first occurrence of str, or -1 on failure
# # # case methods: myString.upper(), myString.lower()
# # # Boolean/is methods: myString.isupper(), myString.isdigit()
#
# LIST
# # again be able to SLICE
# # +
# myList.append(item)
# myList.insert(i, item)
# myList.extend(anotherList)
# # -
# myList.pop() # by index
# myList.remove() # by value
# # other
# myList.count(item)
# myList.sort() # "modify in place", no return
# myList.reverse()

# DICT
# use the key like an index
# myDict[key] # retrieve the value, like myDict.get()
# myDict[key] = new value # set a value, like myDict.update()
# myDict.items() # for looping
# myDict.keys() # returns a set-like object of just the keys
# myDict.values() # returns a list-like object of just the values

# # SETS
# mySet.add()
# mySet.remove(item)
# mySet.pop() # removes a random entry

# MODULES
# MATH
# import math
# math.factorial()
# math.floor()
# math.ceil()
# math.pow() # **, not same as math.exp()
# math.sqrt()
# math.e
# math.pi

# # full vs partial import
# # import math --> math.factorial()
# from math import factorial, sqrt --> factorial()

# OPENING FILES
# # good practice: Ch 12 Task 4, 7, 8

with open("filename.txt", "r") as f:
    # # read() -> whole file as one big string
    # # readlines() -> a list of line by line strings
    myContent = f.readlines()
# if I'm reading I like to leave the with/open() block as soon as I can
# to free up memory.

import csv
with open("filename.csv", "r") as f:
    # myContent = csv.reader(f) # a list-like object of line by line lists of strings
    myContent = list(csv.reader(f))


# write
with open("myNewFile.txt", "w") as f:
    # if you're figuring something out (and maybe looping to create strings)
    # ... you'll probably need to stay in this with/open block as you write the file
    f.write("I am writing a string into this file.")


# student question
numList = [1, -5, 4, 37, -2, 512, -511, 8, -3, -55, 0]
notNegNumList = []
for n in numList:
    if n >= 0: # or > 0 if you don't want 0
        notNegNumList.append(n)
# now notNegNumList has only numbers greater than 0
print(notNegNumList)