Python Tutorial | Python Fiddle

Define a variable
my_variable=10;

Booleans
my_bool=True;
my_new_bool=False;

Comment
# Put the “#” symbol at the start of the line to define a comment

Whitespace matters
# This will NOT run!
def spam():
eggs = 12
return eggs
        
print spam()
5) Proper Whitespace
def spam():
    eggs = 12  #This line is indented because it is in the spam method
    return eggs
        
print spam()

6) Multi-Line Comments - use Triple Quote (“””)
    """ This is a
multi-line comment
ok"""

7) Print Stuff to the console
    a=1
    print a

8) Math
    “”” + , -, /, * 
    ** is exponent
    % is modulo - remainder - 6%5 is 6/5, which is 1 remainder 1, so the answer is 1

9) Here’s an example
meal = 44.50
tax = 0.0675
tip = 0.15

meal = meal + meal * tax
total=meal+meal*tip

print("%.2f" % total) # We’ll get into print formatting further down

10) String Definition:
    brian="Hello life!"

11) Use a backslash for special characters
'This isn't flying, this is falling with style!' # THIS DOESN’T work because python sees 
the single quotes and tries to make something out of it
'This isn\'t flying, this is falling with style!' # The backslash makes it work

12) Indexing string characters
+---+---+---+---+---+---+
| P | Y | T | H | O | N |
+---+---+---+---+---+---+
  0   1   2   3   4   5
“PYTHON”[3] #Returns “H”

13) String lengths
    my_string=”PYTHON”
    print len(my_string) # returns 6

14) Lower-case String Conversions
    my_string = “PYTHON”
	my_lower_string = my_string.lower() # returns “python”, but my_string is still "PYTHON"

15) Upper-case String Conversions
    my_string = “python”
	my_string.lower() # returns “PYTHON”

16) Number to String
pi=3.14
pistr=str(pi)
print pistr

17) Dot notation - use len() and str() for general types of objects (not just strings), but “upper()” and “lower()” are methods of the string object, so they are expressed as my_str.upper()

18) Concatenation - use a “+”
    print "Spam "+"and "+"eggs" # returns “Spam and eggs”

19) Concatenate numbers into a string:
    print "The value of pi is around " + str(3.14)

20) String formatting with variable placement
string_1 = "Camelot"
string_2 = "place"

print "Let's not go to %s. 'Tis a silly %s." % (string_1, string_2)
    # Returns “Let's not go to Camelot. 'Tis a silly place.”

21) Gather Input and another string formatting example
name = raw_input("What is your name?")
quest = raw_input("What is your quest?")
color = raw_input("What is your favorite color?")

print "Ah, so your name is %s, your quest is %s, " \
"and your favorite color is %s." % (name, quest, color)

22) Datetime Library
from datetime import datetime
now = datetime.now()
print now
# Returns 2016-01-16 03:49:53.687654

23) Extract Specific Date and Time Elements
from datetime import datetime
now = datetime.now()
print now # 2016-01-16 03:49:53.687654
print now.year # 2016
print now.month # 1
print now.day # 16

24) Date / String Formatting
from datetime import datetime
now = datetime.now()
print '%s/%s/%s' % (now.year, now.month, now.day) “Returns 2016/1/16

25) Time Formatting
from datetime import datetime
now = datetime.now()
print '%s:%s:%s' % (now.hour, now.minute, now.second) # Returns 3:53:22

26) Conditionals and Flow
def clinic():
    print "You've just entered the clinic!"
    print "Do you take the door on the left or the right?"
    answer = raw_input("Type left or right and hit 'Enter'.").lower()
    if answer == "left" or answer == "l":
        print "This is the Verbal Abuse Room, you heap of parrot droppings!"
    elif answer == "right" or answer == "r":
        print "Of course this is the Argument Room, I've told you that already!"
    else:
        print "You didn't pick left or right! Try again."
        clinic()

clinic()

27) Comparators return True or False
“””Equal to (==)
Not equal to (!=)
Less than (<)
Less than or equal to (<=)
Greater than (>)
Greater than or equal to (>=)”””

28) And / Or / Not
    a=True
    b=False
    a and b # False
    a or b #True
    not b #True

29) ELSE
answer = "'Tis but a scratch!"

def black_knight():
    if answer == "'Tis but a scratch!":
        return True
    else:             
        return False       # Make sure this returns False

30) ELSE IF:
def greater_less_equal_5(answer):
    if answer>5:
            return 1
    elif answer<5:          
            return -1
    else:
        return 0
        
print greater_less_equal_5(4)
print greater_less_equal_5(5)
print greater_less_equal_5(6)

31) IS ALPHA:
	tmp = "TEMP"
    tmp2 = "TEMP2"
	tmp.isalpha() #returns true    
    tmp2.isalpha() #returns false
   
32) Fully functional pig latin coverter:
    pyg = 'ay'

original = raw_input('Enter a word:')
    
    if len(original) > 0 and original.isalpha():
        print original
        word=original.lower()
        first=word[0]
        new_word=word+first+pyg
        new_word=new_word[1:len(new_word)]
        print new_word
    else:
        print 'empty'
 
 33) FUNCTIONS example:
    def tax(bill): # accepts bill as an input
        """Adds 8% tax to a restaurant bill."""
        bill *= 1.08
        print "With tax: %f" % bill
        return bill # returns bill as a result to be stored in the new variable
    
    def tip(bill): # This is the definition of the function "tip".  Note that the function doesn't have an end - return ends the function
        """Adds 15% tip to a restaurant bill."""
        bill *= 1.15
        print "With tip: %f" % bill
        return bill
        
    meal_cost = 100
    meal_with_tax = tax(meal_cost)
    meal_with_tip = tip(meal_with_tax)
    
34) FUNCTIONS must be CALLED!
    def square(n):
        """Returns the square of a number."""
        squared = n**2
        print "%d squared is %d." % (n, squared)
        return squared
         
    # Here is the function call:
    square(10) #call the function 'square' with the parameter 10
    
35) Functions can call other functions
	def one_good_turn(n):
    return n + 1
    
    def deserves_another(n):
        return one_good_turn(n) + 2
        
    print deserves_another(3)
    
36) IMPORT LIBRARIES
    import math
    
    print math.sqrt(25)
    
37) IMPORT A METHOD FROM A LIBRARY (SO YOU CAN CALL "sqrt" instead of "math.sqrt")
    from math import sqrt
    
    print sqrt(25)
    
38) UNIVERSAL IMPORT - BRING IN ALL FUNCTIONS
	from math import *
    
39) GET A LIST OF ALL IMPORTED METHODS
    import math            # Imports the math module
    everything = dir(math) # Sets everything to a list of things from math
    print everything       # Prints 'em all!
    
40) Other built-in functions - max(), min(), abs()
    def biggest_number(*args): #NOTE THE "(*args)".  This tells python to expect an unspecified number of arguments
        print max(args)
        return max(args)
        
    def smallest_number(*args):
        print min(args)
        return min(args)
    
    def distance_from_zero(arg):
        print abs(arg)
        return abs(arg)
    
    
    biggest_number(-10, -5, 5, 10)
    smallest_number(-10, -5, 5, 10)
    distance_from_zero(-10)
    
41) Get the type of a variable
    # Print out the types of an integer, a float,
    # and a string on separate lines below.
    
    print type(4) # <type 'int'>
    print type(2.2) # <type 'float'>
    print type ('ABC') # <type 'str'>
    
42) EXAMPLE FUNCTION WITH DEFINITION, ARGUMENTS, AND CONDITIONAL FLOW:
    def shut_down(s):
    
    if s=="yes":
        return "Shutting down"
    elif s=="no":
        return "Shutdown aborted"
    else:
        return "Sorry"  #Again, not no end of function line
        
        
    print shut_down('yes') #the function will not run unless called
    print shut_down('no')
    print shut_down(12)
    
43) Sample function that checks variable types:
    def distance_from_zero(x):
     if type(x)==int or type(x)==float:
        return abs(x)
     else:
        return "Nope"
     
    print distance_from_zero(1)
    print distance_from_zero(1.1)
    print distance_from_zero("k")
    
44) Sample of calculating vacation cost - pull in variables from multiple functionns
    def hotel_cost(nights):
        return 140*nights
    
    def plane_ride_cost(city):
        if city=="Charlotte":
            return 183
        elif city=="Tampa":
            return 220
        elif city=="Pittsburgh":
            return 222
        elif city=="Los Angeles":
            return 475
        
    def rental_car_cost(days):
        if days>=7:
            return 40*days-50
        elif days>=3:
            return 40*days-20
        else:
            return 40*days
    
    def trip_cost(city,days,spending_money):
        return hotel_cost(days)+plane_ride_cost(city)+rental_car_cost(days)+spending_money
        
        
    print trip_cost("Los Angeles",5,570)

45) Lists - store multiple datatypes in one variable
        zoo_animals = ["pangolin", "cassowary", "sloth", "zebra"]; # One animal is missing!
    
    if len(zoo_animals) > 3:
        print "The first animal at the zoo is the " + zoo_animals[0] #The list's first item is at index 0, not 1!
        print "The second animal at the zoo is the " + zoo_animals[1]
        print "The third animal at the zoo is the " + zoo_animals[2]
        print "The fourth animal at the zoo is the " + zoo_animals[3]

46) You can access or assign items to a list():
    abc = ["Aa","Bb","Cc"]
    print abc[0] # returns Aa
    abc[2]="Dd" # places "Dd" at index 2 (in place of "Cc")
    
47) Append to a list
	abc = ["Aa","Bb","Cc"]
    abc.append("Dd")
    abc[3] #Will return "Dd"
    
48) Access a portion of a list
	abc = ["Aa","Bb","Cc","Dd","Ee"]
    print abc[1:3] "Returns "Bb", "Cc", and "Dd"

49) Slice a list from the start or end:
    abc = ["Aa","Bb","Cc","Dd","Ee"]
    print abc[:3] #Returns "Aa", "Bb", "Cc", and "Dd"
    print abc[2:] #Returns "Cc", "Dd", and "Ee"

50) List index
    animals = ["aardvark", "badger", "duck", "emu", "fennec fox"]
    duck_index = animals.index("duck")    # Use index() to find "duck" # would return 2
    
51) List insert (not append)
	animals = ["aardvark", "badger", "duck", "emu", "fennec fox"]
    duck_index = animals.index("duck")    # Use index() to find "duck" #duck_index is 2
    
    animals.insert(duck_index,"cobra") #Puts "cobra" before duck_index (makes cobra index 2, the third item in the list, in front of duck
    
    print duck_index,animals # duck_index is 2, which now contains cobra, so this will print "cobra"
    
52) Iterate over each item in a list:
    my_list = [1,9,3,8,5,7]

for number in my_list:
        # Your code here
        print 2*number # Returns 2, 18, 6, 16, 10, 14

53) List Sort
	my_list.sort() # sorts from lowest to highest
    
54) Dictionaries - like lists, but use a key:value pair to find items (instead of an index as in a list) NOTE THE CURLY BRACES IN A DICTIONARY COMPARED TO THE HARD BRACKETS IN A LIST
    # Assigning a dictionary with three key-value pairs to residents:
    residents = {'Puffin' : 104, 'Sloth' : 105, 'Burmese Python' : 106} #The first item's key is Puffin, and the value is 104
    
    print residents['Puffin'] # Prints Puffin's room number
    
    # Your code here!
    print residents['Sloth']
    print residents['Burmese Python']
    
55) Dictionaries are mutable - you can add and remove items from them:
    menu = {} # Empty dictionary
    menu['Chicken Alfredo'] = 14.50 # Adding new key-value pair
    print menu['Chicken Alfredo']
    
    # Your code here: Add some dish-price pairs to menu!
    menu['Sushi']=17
    menu['Pasta']=13
    menu['Dosa']=10
    
    print "There are " + str(len(menu)) + " items on the menu."
    print menu
    
56)

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