Python Essentials 1
One more time, these notes are not meant to be useful for anyone else but me. I am not caring that much about formatting or presentation. I am posting it as a record that I am doing something (which motivates me to keep learning) and as future quick reference instead of going to Google. ( Like this at least I visit my blog :( )
So, here it is…
append.py
print("=========================\n")
### Create a list
my_list = [1, 2, 3, 4, 5]
### Print the list
print(my_list)
### print the lenght of the list
print(len(my_list))
print("=========================\n")
### Append 6 to the end of the list
my_list.append(6)
print(my_list)
print("The lenght of my_list is: ", len(my_list))
print("=========================\n")
my_list.append(7)
print(my_list)
print("The lenght of my_list is: ", len(my_list))
print("=========================\n")
my_list.insert(7, 99)
print(my_list)
bitwise.pycat bitwise.py
x = 4
y = 1
a = x & y
# a = 0100 & 0001
# a = 0000
# a = 0
b = x | y
# b = 0100 | 0001
# b = 0101
# b = 5
c = ~x # tricky!
# c = ~(0100)
# c = 1011
# c = 11
d = x ^ 5
# d = 0100 ^ 0101
# d = 0001
# d = 1
e = x >> 2
# e = 0100 >> 2
# e = 0001
# e = 1
f = x << 2
# f = 0100 << 2
# f = 010000
# f = 16
print(a, b, c, d, e, f)
x = 4
y = 1
a = x & y
# a = 0100 & 0001
# a = 0000
# a = 0
b = x | y
# b = 0100 | 0001
# b = 0101
# b = 5
c = ~x # tricky!
# c = ~(0100)
# c = 1011
# c = 11
d = x ^ 5
# d = 0100 ^ 0101
# d = 0001
# d = 1
e = x >> 2
# e = 0100 >> 2
# e = 0001
# e = 1
f = x << 2
# f = 0100 << 2
# f = 010000
# f = 16
print(a, b, c, d, e, f)
break.py
print("The break instruction")
for i in range(1,6):
if i == 3:
break
print("Inside the loop.", i)
print("Outside the loop")
continue.py
print("\n The continue instruction:")
for i in range(1,6):
if i == 3:
continue
print("Inside the loop.", i)
print("Outside the loop.")
delete.py
numbers = [10, 5, 7, 2, 1]
print("Original list content:", numbers) # Printing original list content.
numbers[0] = 111
print("\nPrevious list content:", numbers) # Printing previous list content.
numbers[1] = numbers[4] # Copying value of the fifth element to the second.
print("Previous list content:", numbers) # Printing previous list content.
print("\nList's length:", len(numbers)) # Printing previous list length.
del numbers[1] # Removing the second element from the list.
print("New list's length:", len(numbers)) # Printing new list length.
print("\nNew list content:", numbers) # Printing current list content.
empty_list.py
my_list = [] # Create an empty list
for i in range(10):
my_list.append(i+1)
print(my_list)
##
print("============================\n")
my_list = [] # Creating an empty list.
for i in range(10):
my_list.insert(0, i + 1)
print(my_list)
break.py
for ch in "john.smith@pythoninstitute.org":
if ch == "@":
break
print(ch, end=" ")
guess_number.py
cat guess_number.py
print(
"""
+================================+
| Welcome to my game, muggle! |
| Enter an integer number |
| and guess what number I've |
| picked for you. |
| So, what is the secret number? |
+================================+
""")
number_to_guess = 10
number_entered_by_user = int(input("Try to guess the magician number: "))
while number_to_guess != number_entered_by_user:
print("Ha ha! You're stuck in my loop!\n")
number_entered_by_user = int(input("Try to guess the magician number: "))
print("Well done, muggle! You are free now.\n")
indexing.py
numbers = [10, 5, 7, 2, 1]
print("Original list contents: ", numbers)
numbers[0] = 111
print("Original list contents: ", numbers)
numbers[1] = numbers[4]
print("Original list contents: ", numbers)
numbers_len = len(numbers)
print(numbers_len)
iterating.py
example = [10, 40, 20, 20, 20]
total = 0
for i in range(len(example)):
total += example[i]
print(total)
## In the below example, the variable "i" takes the value of the item in the list. Unlike the previous example
## where "i" was taking the index.
print("====================")
print("====================")
my_list = [10, 1, 8, 3, 5]
total = 0
for i in my_list:
total += i
print(total)
loop1.py
for i in range (2,8):
print("The value of i is currently:", i)
print("=================================n")
## For with 3 arguments
for j in range(2,8,3):
print("The value of j is currently:", j)
mississippis_count.py
import time
# Write a for loop that counts to five.
i = 1
for i in range(6):
# Body of the loop - print the loop iteration number and the word "Mississippi".
print(i, "Mississippi")
# Body of the loop - use: time.sleep(1)
time.sleep(1)
# Write a print function with the final message.
more_practicing.py
# step 1: create an empty list named beatles;
beatles = []
# step 2: use the append() method to add the following members of
# the band to the list: John Lennon, Paul McCartney, and George Harrison;
beatles.append("John Lennon")
beatles.append("Paul McCartney")
beatles.append("George Harrison")
print(beatles)
# step 3: use the for loop and the append() method to prompt the user
# to add the following members of the band to the list: Stu Sutcliffe, and Pete Best;
number_of_members_to_add = int(input("Please, specify the amount of members to add: "))
i = 0
for i in range(number_of_members_to_add):
beatles.append(input("Please, enter the name of the Beatle member to add: "))
print(beatles)
# step 4: use the del instruction to remove Stu Sutcliffe and Pete Best from the list;
del beatles[3:]
print(beatles)
# step 5: use the insert() method to add Ringo Starr to the beginning of the list.
beatles.insert(0, "Ringo Starr")
print(beatles)
odd_even.py
# A program that reads a sequence of numbers
# and counts how many numbers are even and how many are odd.
# The program terminates when zero is entered.
odd_numbers = 0
even_numbers = 0
# Read the first number.
number = int(input("Enter a number or type 0 to stop: "))
# 0 terminates execution.
while number != 0:
# Check if the number is odd.
if number % 2 == 1:
# Increase the odd_numbers counter.
odd_numbers += 1
else:
# Increase the even_numbers counter.
even_numbers += 1
# Read the next number.
number = int(input("Enter a number or type 0 to stop: "))
# Print results.
print("Odd numbers count:", odd_numbers)
print("Even numbers count:", even_numbers)
odd_with_while.py
x = 1
while x < 11:
if x % 2 != 0:
print(x)
x += 1
print_odds_from0_to_10.py
for i in range(1, 11):
if i % 2 != 0:
print(i)
scenario.py
hat_list = [1, 2, 3, 4, 5] # This is an existing list of numbers hidden in the hat.
# Step 1: write a line of code that prompts the user
# to replace the middle number with an integer number entered by the user.
hat_list[2] = int(input("Please, enter a number: " ))
# Step 2: write a line of code that removes the last element from the list.
del hat_list[-1]
# Step 3: write a line of code that prints the length of the existing list.
print(len(hat_list))
print(hat_list)
studying.py
# Store the current largest number here.
largest_number = -999999999
# Input the first value.
number = int(input("Enter a number or type -1 to stop: "))
# If the number is not equal to -1, continue.
while number != -1:
if number > largest_number:
largest_number = number
number = int(input("Enter a number or type -1 to stop: "))
# Print the largest number.
print("The largest number is:", largest_number)
swapping.py
my_list = [1, 2, 3, 4, 5]
length= len(my_list)
for i in range(length // 2):
my_list[i], my_list[length - i - 1] = my_list[length - i - 1], my_list[i]
print(my_list)