Algorithms • 17 min read

ALGORITHMS

SRSC

BIG IDEA: A FINITE SET OF INSTRUCTIONS THAT ACCOMPLISH A SPECIFIC TASK

SEQUENCING

DO STEPS OF CODE IN THE ORDER SPECIFIED

first step -> second step -> third step

number = int(input("Enter a number: "))

result = number * 2
print("double of " + str(number) + " is " + str(result))

double of 1is 2

1. Create a variable based on user input
   
2. Multiply variable by two
   
3. Print out both variables at the end
   

SELECTION

Choose TWO OR MORE OUTCOMES based on a DECISION or CONDITION

number = 6
if number % 2 == 0:
    print("Even")
else:
    print("Odd")

Even

1. Set number to 5
   
2. If number is divisible by 2 with no remainder, print “Even”
   
3. Otherwise, print “Odd”
   

ITERATION

REPEAT STEPS BASED ON A DECISION or STOP when a condition is met

first step -> second step -> if step 2: true -> first step if step 2: false -> third step -> fourth step

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)

apple
banana
cherry

1. Create a list called fruits
   
2. For each fruit in the list, print the fruit

ACTIVITY 1: Robot Pseudocode

Link to Robot Question 2

Write the pseudocode to move the robot onto the gray square.

Available Code:
Move forward
Turn Left
Turn Right

Move forward Move forward Move forward Turn Left Move forward Move forward Turn Right Move forward Move forward Move forward

PseudoCode here:

# Math Operations:

print("Addition") #addition
result = 5 + 3
print(result)  # 8

print("\nSubtraction") #subtraction
result = 10 - 4
print(result)  # 6

print("\nMultiplication") #multiplication
result = 6 * 7
print(result)  # 42

print("\nFloat Division") #float division (float = numbers with decimal values)
result = 20 / 4
print(result)  # 5.0

print("\nInteger Division (floor division)") #floor division
result = 20 // 4
print(result)  # 5

print("\nModulus (remainder)") #remainder
result = 10 % 3
print(result)  # 1

Addition
8

Subtraction
6

Multiplication
42

Float Division
5.0

Integer Division (floor division)
5

Modulus (remainder)
1

Fibonacci
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

Factorial
120

Fibonacci

def fibonacci(n): #fibonacci sequence 
    fib_series = [0, 1]  

    while len(fib_series) < n:
        next_number = fib_series[-1] + fib_series[-2]  
        fib_series.append(next_number)  

    return fib_series

n = 10  
result = fibonacci(n)
print(result)  # [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

# initial length of list is 2 
# while length of list is less than amount of numbers we want in our final sequence
# add the last two numbers of the list 
# add this value to the end of the list 
# repeat until length of list reaches n

[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

Mini Lesson: If, Else Statements

num =0

if num > 0:
    print(str(num) + " is positive.")
elif num < 0:
    print(str(num) + " is negative.")
else:
    print(str(num) + " is zero.")

0 is zero.

Mini Lesson 2: For, While Loops

names = ["Alice", "Bob", "Charlie", "David", "Eve"]
for name in names:
    print(name)


num = 1
while num <= 5:
    print(num)
    num += 1

Alice
Bob
Charlie
David
Eve
1
2
3
4
5

Mini Lesson 3: Defining Function

def calculate_square(number):
    square = number * number
    return square #ends function 

result = calculate_square(5)
print(f"The square of 5 is {result}")

The square of 5 is 25

Mini Lesson 4: Input

variable1 = input("How old are you?")
print("You are " + variable1 + " years old")

You are asd years old

ACTIVITY 2: CALCULATOR

1. Create calculator function
   
2. Allow user to Choose 2 numbers and an operator
   
3. Perform specified operation based on input
   
4. Return result of calculation
   

##YOUR WORK HERE 
##Hint: Use if else statements, defining functions, input
def calculator(num1, num2, operation)
    if 

# String Operations and Concatenation:

print("\nString Concatenation") #add together strings
str1 = "Hello"
str2 = "World"
result = str1 + " " + str2
print(result)  # "Hello World"

print("\nString Length") #length of string
text = "This is a sample text."
length = len(text)
print(length)  # 22

print("\nString Indexing and Slicing") #string slicing 
text = "Python"
first_char = text[0]
substring = text[2:5]
print(first_char)  # 'P'
print(substring)  # 'tho'


print("\nString Repetition (Repeating Strings)")
text = "Repeat "
result = text * 3
print(result)  # "Repeat Repeat Repeat "

# Palindrome Check Algorithm:

print("\nPalindrome Check Algorithm")

def is_palindrome(text):
    text = text.replace(" ", "").lower()
    return text == text[::-1] ## == will return boolean 

result1 = is_palindrome("racecar")
result2 = is_palindrome("Hello, World!")

print(result1)  # True
print(result2)  # False

String Concatenation
Hello World

String Length
22

String Indexing and Slicing
P
tho

String Repetition (Repeating Strings)
Repeat Repeat Repeat 

Palindrome Check Algorithm
True
False

ACTIVITY 3: COUNTING VOWELS

1. Create a function that takes a word as an input
   
2. Use a for loop to iterate through each character of a word
   
3. Check how many characters in a word contain vowels
   
4. Return vowel number
   

##YOUR WORK HERE
input = "supercalifragilisticexpialidocious"

vowels = set("aeiouAEIOU")
vowel_count = 0

for character in input:
    if character in vowels:
        vowel_count +=1

print(vowel_count)

16

HOMEWORK

CREATE TEXT (string) ANALYZER:

criteria:

1. Accepts input from user
   
2. Counts total letters, numbers, spaces in a string
   
3. Counts number of vowels
   
4. Calculates average word length
   
5. Correctly displays: total # of characters (including spaces + numbers), total vowels, average word length
   

   other criteria:
   

6. ensure that program handles upper and lowercase spelling
   
7. Test multiple inputs to ensure accuracy

   Criteria for above 90%:
   

8. Add a unique program, function, or feature not specified by criterias

word = input("input a word:")

total_character = 0
total_letter = 0
total_number = 0
total_space = 0
total_vowel = 0

for char in word:
    total_character +=1
    if char.isalpha():
        total_letter += 1
    if char.isnumeric():
        total_number += 1
    if char.isspace():
        total_space += 1
    if char in 'aeiou':
        total_vowel += 1
    total_character += 1

word_length = 0

words = word.split()

average_word_length = total_letter / len(words)

print("For the word(s) " + "'" + word + "'" + ": ")
print("Total characters (including spaces and numbers)=", total_character)
print("Total letters=", total_letter)
print("Total numbers=", total_number)
print("Total spaces=", total_space)
print("Total vowels=", total_vowel)
print("Average word length=", average_word_length)


# Additional function
from collections import Counter
word_counts = Counter(words)
most_common_words = word_counts.most_common(5)  

print("Amount of times each word occurs: ")

for word, count in most_common_words:
    print(f"{word}: {count} times")

For the word(s) 'i have a dog and i want a cat': 
Total characters (including spaces and numbers)= 58
Total letters= 21
Total numbers= 0
Total spaces= 8
Total vowels= 10
Average word length= 2.3333333333333335
Amount of times each word occurs: 
i: 2 times
a: 2 times
have: 1 times
dog: 1 times
and: 1 times