Reverse Polish Notation ParserEdit in new window bubble
task_alt
Reverse Polish Notation ParserEdit in new window bubble
Python Syntax-
keyboardInputsstat_minus_1
- # Text inputname = input("Enter your name:")
- # Whole number inputage = int(input("Enter your age:"))
- # Decimal number inputprice = float(input("Enter a price:"))
-
computerOutputsstat_minus_1
- # Output text print("Hello World")
- # Output text + variable (String) print("Hello " + playerName)
- # Output text + variable (Integer/Float)
score = 5
print("Your score: " + str(score)) - # Clear the screenimport os
os.system("clear")
-
note_stack_addVariables and Arithmetic Operatorsstat_minus_1
- # Initialising variables and constants of different data types:
score = 0
PI = 3.14
message = "Hello World"
soundOn = True - # Arithmetic Operators:
x = a + b # Add
x = a – b # Take away
x = a / b # Divide
x = a * b # Multiply
x = a ** 2 # to the power of x = a // b # Quotient DIV x = a % b # Remainder MOD
x += 1 # Increment x by 1
x -= 1 # Decrement x by 1
x *= 2 # Multiply x by 2
x /= 2 # Divide x by 2 - # Rounding a number:
pi = 3.14159
pi2 = round(pi,2)
print("Pi rounded to two decimal places: " + str(pi2)) # 3.14
- # Initialising variables and constants of different data types:
score = 0
-
arrow_splitSelection: if, elif, else...stat_minus_1
- if numberOfLives == 0:
print("Game Over!") - if numberOfLives == 0 or timer<=0:
print("Game Over!")
else:
print("Carry on playing!") - if number < 0:
print("Negative Number")
elif number == 0:
print("Zero")
else:
print("Positive Number") - if number == 7:
print("Seven")
elif number == 8:
print("Eight")
elif number == 9:
print("Nine")
else:
print("Not seven, eight or nine")
- if numberOfLives == 0:
-
autorenewIteration: for loops & While loopsstat_minus_1
-
# For loop to count from 1 to 10
for i in range(1,11):
print(i) -
# For loop to count in 5 from 0 to 100
for i in range(0,101,5):
print(i) -
# For loop to count down from 10 to 1 using a negative step
for i in range(10,0,-1):
print(i) -
# Iterate through all the values of a list
days = ["Mon", "Tue", "Wed", "Thu", "Fri"]
for i in range(0,len(days)):
print(days[i]) -
# Iterate through all the values of a list - Alternative approach
for day in days:
print(day) -
# Iterate through all the characters of a string
string = "Hello World"
for character in string:
print(character) -
# Using a while loop
i=0
while i<=100:
print(i)
i = i + 1 - # To exit from/break a loop at any time:
while True:
# ...
if timer==0:
break
-
# For loop to count from 1 to 10
for i in range(1,11):
-
settingsFunctionsstat_minus_1
- # Define a new proceduredef displayBanner(message):
print("---------------")
print(message)
print("---------------")
# Procedure call displayBanner("Hello World!") - # Define a new functiondef add(x, y):
sum = x + y
return sum
# Function call total = add(1,3)
print(total) # this would display 4
- # Define a new proceduredef displayBanner(message):
-
match_caseString Manipulationstat_minus_1
-
# String Concatenation
firstname = "James"
lastname = "Bond"
greeting = "Hello " + firstname + " " + lastname
print(greeting) -
# Casting a number into a String
number = 7
print("Your lucky number is " + str(number)) -
# Changing the case of a string
name = "james BOND"
uppercase = name.upper() # JAMES BOND
lowercase = name.lower() # james bond
titlecase = name.title() # James Bond
-
# Retrieving the number of characters in a string
password = "Pa55w0rd"
passwordLength = len(password) # 8
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# String Slicing: Extracting characters from a string
alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
print("The fifth letter of the alphabet is: " + alphabet[4])
print("The first 5 letters of the alphabet are: " + alphabet[:5])
print("The next 5 letters of the alphabet are: " + alphabet[5:10])
print("The last 5 letters of the alphabet are: " + alphabet[-5:]) -
# Iterate through all the characters of a string
string = "Hello World"
for character in string:
print(character)
-
# String Concatenation
firstname = "James"
-
live_helpRandom Librarystat_minus_1
-
# Import the random library
import random
- # Generate a random number between 1 and 100 randomNumber = random.randint(1,100)
-
# Pick a value in a list at random
names = ["Fred","Ali","Ines"]
randomName = random.choice(names) -
# To shuffle a list
numbers = [1,2,3,4,5]
random.shuffle(numbers) - # Use ASCII codes to generate a random letter between A and Z randomLetter = chr(random.randint(65,90))
-
# Import the random library
import random
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storageData Structures: Lists, Tuples and Dictionariesstat_minus_1
-
# Declaring a list and accessing its values
days = ["Mon","Tue","Wed","Thu","Fri","Sat"]
days.append("Sun")
print(days[0]) # "Mon"
print(days[1]) # "Tue"
print(days[2]) # "Wed
…
print(days[6]) # "Sun" - # Finding out the number of items in a list (length of a list) print(len(days)) # 7
-
# Iterate through all the values of a list
for i in range(0,len(days)):
print(days[i]) -
# Iterate through all the values of a list - Alternative method
for value in days:
print(value) -
# Adding a new value at the end of a list
numbers = [1,3,5]
numbers.append(7) -
# Removing a value from a list
days = ["Mon","Tue","Wed","Thu","Fri"]
numbers.remove("Wed") -
# Removing a value from a list at a given position
days = ["Mon","Tue","Wed","Thu","Fri"]
numbers.pop(2) # remove the third item from this list: "Wed"
-
# Declaring a tuple
magenta = (255,0,255)
print("R: " + str(magenta[0]))
print("G: " + str(magenta[1]))
print("B: " + str(magenta[2])) -
# Using a Dictionary (Hash table)
dictionary = {"One":"Un", "Two":"Deux", "Three":"Trois"}
print("One in French is " + dictionary["One"])
-
# Declaring a list and accessing its values
days = ["Mon","Tue","Wed","Thu","Fri","Sat"]
- # Adding an extra key to a dictionary dictionary["Four"] = "Quatre"
descriptionFile Handlingstat_minus_1
-
# Reading a text file, line by line
file = open("myTextFile.txt","r")
for line in file:
print(line)
file.close() -
# Reading and extracting data from a CSV file, line by line
file = open("myTextFile.txt","r")
for line in file:
data = line.split(",")
print(data[0] + " - " + data[1] + " - " + data[2])
file.close() -
# Overwriting the content of a text file
file = open("myTextFile.txt","w")
file.write("Hello World\n")
file.close() -
# Appending data at the end of a text file
file = open("myTextFile.txt","a")
file.write("Hello World\n")
file.close()
select_check_boxInput Validationstat_minus_1
-
# Input Validation: Presence Check
name = input("Enter your name:")
if name=="":
print("Empty name!")
else:
print("Thank you!") -
# Input Validation: Type Check – Integer?
number = input("Type a number:")
if number.isdigit():
print("This is a number")
else:
print("This is not a whole number") -
# Input Validation: Range Check
number = int(input("Type a number between 1 and 5:"))
if number>=1 and number<=5:
print("Valid number")
else:
print("Invalid number") -
# Input Validation: Lookup Check
drive = input("Can you drive?").lower()
if drive in ["yes","no"]:
print("Valid answer")
else:
print("Invalid answer") -
# Input Validation: Character Check
email = input("Type your e-mail address:")
if "@" in email:
print("Valid e-mail address")
else:
print("Invalid e-mail address") -
# Input Validation: Length Check
password = input("Type a password:")
if len(password)>=8:
print("Valid password")
else:
print("Invalid password") -
# Try Again! Using a While Loop:
name = input("Enter your name:")
while name=="":
print("You must enter your name! Please try again!")
name = input("Enter your name:")
print("Welcome " + name)
manufacturingOOPstat_minus_1
- import random
# Defining a Dice class class Dice(): # Constructor for the Dice class def __init__(self,numberOfSides=6):
self.numberOfSides = numberOfSides
self.value = 1
def throw(self):
self.value = random.randint(1,self.numberOfSides)
return self.value
# Instantiating a dice object using the Dice class dice = Dice(6)
dice.throw()
print(dice.value)