my_secret_num = 1
myName = "Mark"
isDone = False
_ = None

# A variable name must not start with a number or a special character except underscore "_"

0_1 = 1 # raises a Syntax Error
dollar$= "$ss" # raises a Syntax Error
@_2 = 1 # raises a Syntax Error

if True:
    print("Indentation Rocks") # This statement has 4 spaces before it.

i = 0
while True:
    if i == 2: # This statement has 4 spaces before it.
        break # This statement has 8 spaces before it.
    else:       # This statement has 4 spaces before it.
        i += 1 # This statement has 8 spaces before it.

def func():
    pass  # This statement has 4 spaces before it.

for num in [1,2,3]:
print(num) # This raises an Error SyntaxError: expected an indented block

my_first_name = "Mark" # String
my_fav_num = 21 # Number - Integer
my_fav_float_num = 21.0 # Number - Float

is_current_year_odd = False # Boolean - True | False
wish_list = ["new video card","new monitor","new keyboard"]  # List
language_profiencies = { # Dictionary
     "Python" : 6.5,
     "JavaScript" : 8.5
     "TypeScript" : 7
}
cant_change_this = ("Global Warming","is","Real") # Tuple
nums = {1,2,3,4,5,1} # Set
sample_file_data = open("path/to/file.txt","a") # File

print("Hello " + "World") # This prints Hello World
# string concatenation

print("Hello" * 3) # This prints HelloHelloHello
# string repetition

print([1,2,3] + [4,5]) # This prints [1,2,3,4,5] 
# + combines both list

print([1] * 3) # This prints [1,1,1]
# * list repetition.

is_done = True

if is_done:
   print("The job is done") # This will be printed because the variable "is_done" is True
else:
   print("The job is not done") # This will not print 

my_grade = "B"

if my_grade == "A":
    print("Amazing")
elif my_grade == "B":
    print("Very Good")  # This will be printed
elif my_grade == "C":
    print("Good")
elif my_grade == "D":
    print("Bad")
elif my_grade == "E":
    print("Very Bad")
else:
    print("Failed")

count = 0
while count < 5:
    print(count)
    count += 1

avengers = ["Iron Man", "Captain America","Thor", "Hulk", "Black Widow", "Hawkeye"]

for avenger in avengers:
    print(avenger) 

print(range(5)) # This prints range(0,5)
print(range(0,5,1)) # This is equivalent in the print statement above
print(range(0,5)) # This is equivalent in the print statement above

# We can convert the return value of the range function into a List. Using the list function

print(list(range(5))) # This prints [0,1,2,3,4] does not include the stop

print(len("abc")) # This prints 3. The number of characters in the String
print(len([1,2,3,4,5])) # This prints 5. The number of values in the List
print(len((1,2,3,4))) # This prints 4. The number of values in the Tuple
print(len({1,2,3,3})) # This prints 3. The number of values in the Set
print(len({"a":"eyy","b":"bee","c":"si"})) # This prints 3. The number of keys in the Dictionary

for index in range(len(avengers)):
    print(f"{index} - {avengers[index]}") # This prints the index and the corresponding value at that index in each iteration

i = 0
while True:
    count += 1
    if count == 3:  # When the value of count is 3. This loop will exit
        break
    else:
        print(count)

for avenger in avengers:
    if avenger == "Thor":  # When the value of avenger is Thor. This loop will exit
        break
    else:
        print(avenger)

i = 0
while True:
    count += 1
    if count == 3:  # Will not print 3
        continue
    else:
        print(count)

for avenger in avengers:
    if avenger == "Thor":  # Will not print Thor
        continue
    else:
        print(avenger)

is_absent = False
my_fav_num = 5

print(is_absent) # This prints False
print(my_fav_num > 1) # This True because it compares if 5 is greater than 1 which evaluates to True
print(True and False) # This prints False
print(True or False) # This prints True
print(not False) # This prints True

if is_absent:
    print("Mark is present")  # This will not be printed because is_absent is False
else:
    print("Mark is absent")  # This will be printed

while True:  # This is an example of an infinite loop
    print("This will not stop")  # Press Ctrl+C to Stop

print(True == 1) # This prints True
print(False == 0) # This prints True

my_name = "Mark"

my_favorite_language = 'Python'

my_favorite_book = 'The Sum of all Fears"
# This will raise a SyntaxError because it starts with a single-quote but ends with a double-quote

first_letter = my_name[0] # returns the first character in my_name variable which is "M"

print(first_letter) # This will print "M"

first_letter = my_name[-4] # returns the first character in my_name variable which is also "M" using negative-indexing

print(first_letter) # This will print "M"

guess_my_value = my_name[0:4:1]
# It will extract the portion of the characters from index 0 to index 4 but not including, with a step of 1
# so it extract 'M', 'a', 'r', 'k' with an index of 0,1,2,3 respectively. The step has a default value of 1.

print(guess_my_value) # This will print "Mark"

print(my_name[0:4]) # This will still print "Mark"

print(my_name[:]) # This will still print "Mark"

print(my_name[0:]) # This will still print "Mark"

my_name[0] = "A" # This will raise a TypeError 'str' object does not support item assignment
my_name = "Polo" # This assigns a new value for my_name
print(my_name) # This will print "Polo"

my_name = "Mark"

print(my_name.upper()) # This prints "MARK"
# The "upper" method returns a new string version as all in uppercase

print(my_name.lower()) # This prints "mark"
# The "lower" method returns a new string version as all in lowercase

print(my_name.islower()) # This prints False
# The "islower" method returns a Boolean indicating if the String contains all lowercase letters
# it returns True if all letters are lowercase else return False

print(my_name.isupper()) # This prints False
# The "isupper" method returns a Boolean indicating if the String contains all uppercase letters
# it returns True if all letters are lowercase else return False

print(my_name.isalpha()) # This prints True
# The "isalpha" method returns a Boolean indicating if all characters in the String 
#  are alphabetic  it returns True else it returns False

print(my_name.isdigit()) # This prints False
# The "isdigit" method returns a Boolean indicating if all characters in the String
# are numbers it returns True else it returns False

print(my_name.index("ark")) # This prints 1
# The "index" method searches a substring in String and returns the starting Index
# of the substring else this method raises a ValueError.

print("a,b,c,d".split(",")) # This prints ["a","b","c","d"]
# The "split" method obviously splits the String with parameter separator and returns a
# list of all strings. It also has a second parameter which is a number that indicates 
# the number of splits we want.

print(my_name.startswith("Ma")) # This prints True
# The "startswith" method returns a Boolean indicating if the String
# starts with a certain substring else it returns False     

print(my_name.startswith("rc")) # This prints False
# The "endswith" method returns a Boolean indicating if the String
# ends with a ceratin substring else it returns False   

import fractions
import decimal

my_num = 5 # Integer
pi = 3.14 # Floating-point number
ten = 0o012 # Octal
x = 0x123 # Hex
two = 0b010 # Binary
unique_nums = {1,2,3,2,3} # Sets
is_done = True # Boolean
one_and_a_half = fractions.Fraction(1/2)  # Fraction
one_over_three = decimal.Decimal(1/3) # Decimal

print(str(2) + "is two")
print(str(3.0) + "is three")
print(4.1+ "is four point one") This raises a TypeError: unsupported operand type(s) for +: 'float' and 'str'

print(True == 1) # This prints True
print(False == 0) # This prints True
print(isinstance(True,int)) # This prints True

numbers = [1,2,3,4,5]

one = numbers[0] # numbers[0] holds the value of 1in the List
two = numbers[1] # numbers[1] holds the value of 2 in the List
five = numbers[-1] # numbers[-1] holds the value of 5 in the List

# We can get the length of the array using the "len" method. We only pass the name of the variable that holds the List.

len_of_numbers = len(numbers) # len(numbers) returns 5

# If we access an index that is more than the number of values in the List
# you will get an IndexError

guess_this_number = numbers[1000] # This will raise the IndexError

avengers = ["Iron Man","Captain America","Thor","Hulk","Black Widow","Hawkeye"]

for avenger in avengers: 
      print(avenger) # prints every avenger each in a new line

# If you want to use the index instead of the value
# we can also use that using for loops with the help of "range" and "len" functions

for index in range(len(avengers)):
      print(index) # prints the index each in a new line

# Tip: Instead of checking the length of a List in a condition
# just use the list instead

data = ["one"] 

if len(data):
    print("This will be printed.")

# Use this instead

if data:
    print("This will be printed.")

l = [1,2,3,4,5]

# list[start:stop:step] 

len_l = len(l) # has a value of 5
half = len_l//2

first_half = l[0:half] # l[0:half] will evaluate to l[0:2] is also equivalent to l[:2]

print(first_half) # This will print [1,2]

second_half = l[half:len_l] # l[half:l] will evaluate to l[2:5] is also equivalent l[2:] 

print(second_half) # This will print [3,4,5]

odd_nums = l[0:len_l:2] 
#  l[0:len_l:2] will evalute to l[0:5:2] the 0 our start, the 5 is our stop and the step is 2 
#  l[0:5:2] is also equivalent to l[0::2] or l[::2]

print(odd_nums) # This will print [1,3,5]

reverse_l = l[::-1] 
#  l[::-1] This reverse the start and stop meaning we will start at the last item and stop 
# with the first item. [::-1] is also equivalent to l[len(l)::-1]

print(reverse_l) # This will print [5,4,3,2,1]

avengers.append("Ant-Man") 
# The "append" method add a new item at
#  the end of List

avengers.count("Iron Man") # returns 1
# The "count" method counts how many times
#  the value passed appears

avengers.extend(["Doctor Strange","Spiderman","Black Panther"])
# The "extend" method adds all items 
# passed at the end of the List. The parameter passed must be an Iterable object.

avengers.index("Captain America") # returns 1
# The "index" method returns the first index of the value passed.
# If the value does not exist this method raises a ValueError.

avengers.insert(0,"Captain Marvel")
# The "insert" method obviously inserts a value 
# at a specified index but does not replace the
#  current value at that position.

avengers.append("Thanos")
avengers.remove("Thanos") # returns 1
# The "remove" method obviously removes the first occurence of the value passed.
# If the value does not exist this method raises a ValueError.

avengers.reverse()
# The "reverse" method reverses the position of each item in the List.
# If the List looks like this my_list = [1,2,3]
# then we use l.reverse()
# then my_list would look like this [3,2,1]

avengers.pop()
# The "pop" method removes the last item in the List and returns it.
# We can specify the index to remove in pop method as a parameter
# If the index is not valid or if the List is empty this method raises an 
# IndexError.

my_favorite_numbers = (1,21,19)

# If you only assign one value in the Tuple without using a comma 
# Python will treat that as an expression and in turn that variable
# will not be a tuple instead will the first item in the parentheses

my_secret_nums = (666) 

print(my_secret_nums) # will print 666 instead of (666)

my_new_secret_nums = (666,)

print(my_new_secret_nums) # prints (666,)

secret_hero_real_names = ("Bruce Wayne","Steve Rogers","Clark Kent","Peter Parker")

secret_hero_real_names.count("Bruuce Wayne") #returns 0
secret_hero_real_names.count("Peter Parker") #returns 1 
secret_hero_real_names.index("Steve Rogers") # returns 1

books_currently_reading_bookmark = {
   "Angel & Demons" :  484,
   "Da Vinci Code": 100
}

# We can use a key with a type of "string","integer" or "tuples" in Dictionaries

d = { 1 : "one" }
print(d[1]) # prints "one"

d1 = { (1,2,3,4,5,6,7,8,9,10): "one-ten"}

print(d[(1,2,3,4,5,6,7,8,9,10)]) # prints "one-ten"

#We cannot use a type of "dictionary" or "list" as a key in Dictionaries

d2 = { [1,2,3] : "one-three" } # This will raise a TypeError : unhashable type: 'list'

letters_sounds = {}

letters_sounds["a"] = "eyyy"
letters_sounds["b"] = "bee"

print(letters_sound) # prints {'a': 'eyyy', 'b': 'bee'}

print(letters_sounds["c"]) # This will raise a KeyError which means that key "c" does not exist in the letters_sounds Dictionary.

if "c" in letters_sounds: # Check if "c" exists
    print(letters_sounds["c"])
else:
   print("letters_sounds does not have a 'c' key")


print(letters_sounds.get("c") == None) # prints True
# The get method has a second parameter which is the default value 
# that will be used if the key does not exist in the Dictionary

print(letters_sounds.get("c",0)) # prints 0

new_letters_sounds = {
      "a": "ayy",
      "c" : "si"
}

letters_sounds.update(new_letters_sounds) 
# The "update" method adds or updates new keys in the dictionary it accepts 
# an Iterable type as a parameter or the source

letters_sounds.setdefault("c","sii") 
# The "setdefault" method add a new key and a default value in the dictionary
# if the key doesn't exist in the dictionary, if it exists it returns the value of that key

for key in letters_sounds.keys():
    print(key) # This prints "a", "b" and "c" respectively each in a new line
# The "keys" method returns all keys in the dictionary. This does not return a list.
# Instead it returns a set-like object.

for val in letters_sounds.values(): 
    print(val) # This prints "ayy", "bee" and "si" each in a newline
# The "keys" method returns all keys in the dictionary. This does not return a list.
# Instead it returns a set like object.

# If you want to access the key and the value in a loop.
# You can use the "items" method.
for key, value in tuple(letters_sounds.items()):
    print(f"{key}:{value}") # This prints "a:ayy", "b:bee" and "c:si" respectively each in a newline
# The "items" method returns the key and value in a set like object.

letters_sounds.pop("c")
# The "pop" method removes a key and its value in the Dictionary.
# If the key does not exist this raises a KeyError.

letters_sounds.clear()
# The "clear" method removes all the keys and values in the Dictionary.

nums = {1,2,3,4,3,4}
nums_2 = set([1,2,3,4,4,5,5]) 
print(nums)  # This prints {1,2,3,4} because Sets only holds unique values.

print(nums_2) # This prints {1,2,3,4,5}

print(nums[0])
# This raises a TypeError: 'set' object does not support indexing.

nums.add(4) 
# The "add" method adds a new value in Set if it does not 
# already exist. If already exists this method does nothing.

nums.remove(1)
# The "remove" method removes a specific value from the Set.
# If the value does not exist it raises a KeyError.

nums.clear()
# The "clear" method obviously removes all the values present
# in the Set.

s1 = {1,2,3}
s2 = {3,4,5,6}

print(s1 | s2)  # This prints {1,2,3,4,5,6} 
# This operation is called "union" it combines both sets and returns a new set.
# It also have a equivalent method on sets called "union" suprise, suprise.
print(s1.union(s2))  # Also prints {1,2,3,4,5,6} 

print(s1 & s2) # This prints {3}
# This operation is called "intersection" it finds the common elements in both sets and returns it in a set.
# It also have a equivalent method on sets called "intersection" suprise, suprise.
print(s1.intersection(s2))  # Also prints {3}

print(s1 - s2)  # This prints {1, 2}
# This operation is called "difference" it finds the difference between the first Set and the second Set and returns a new Set.
# So in this example it calculates what elements "s1" has that "s2" does not have.
# It also have a equivalent method on sets called "difference" suprise, suprise.
print(s1.difference(s2)) # Also prints {1,2}

print(s1 ^ s2) # This prints {1,2,4,5,6}
# This operation is called "symmetric_difference" it finds the elements that are not common between the two sets and returns it as a Set.
# So in this example it calculates what unique elements between "s1" and "s2" has and returns it.
# It also have a equivalent method on sets called "symmetric_difference" suprise, suprise.
print(s1.symmetric_difference(s2)) # Also prints {1,2,4,5,6}