Python & SQL Exam Cheat Sheet

# Type Casting

age = int("16") # 16 (Integer)

price = float("19.99") # 19.99 (Real/Float)

text = str(42) # "42" (String)

flag = bool(1) # True (Boolean)

# User Input (Always cast numerical input!)

user_name = input("Enter name: ")

user_score = int(input("Enter score: "))

word = "AQA COMPUTER"

len(word) → 12

word.lower() → "aqa computer"

word.upper() → "AQA COMPUTER"

word.find("COMP") → 4 (index of match)

# Slicing: [start:stop] (up to, NOT including stop)

word[0:3] → "AQA" (indices 0, 1, 2)

word[4:] → "COMPUTER" (from 4 to end)

word[-1] → "R" (last character)

# Count-Controlled Loop (for)

for i in range(1, 6): # 1, 2, 3, 4, 5

print(i)

for i in range(10, 0, -2): # 10, 8, 6, 4, 2

print(i)

# Condition-Controlled Loop (while)

attempts = 0

while attempts < 3:

pin = input("Enter PIN: ")

if pin == "1234": break

attempts += 1

# 1D List Operations

fruits = ["Apple", "Banana", "Cherry"]

fruits.append("Date") # Adds to end

fruits[1] = "Blueberry" # Updates Banana

len(fruits) → 4

# 2D Array: grid[row][column]

grid = [

[10, 20, 30], # row 0

[40, 50, 60] # row 1

]

val = grid[1][2] # Row 1, Col 2 → 60

# Nested Loop Traversal

for r in range(len(grid)):

for c in range(len(grid[r])):

print(grid[r][c])

# Reading line by line until End-Of-File

my_file = open("scores.txt", "r")

line = my_file.readline().strip()

while line != "":

print(line)

line = my_file.readline().strip()

my_file.close() # Always close!

# Writing / Appending to file

my_file = open("log.txt", "w") # "w" overwrites, "a" appends

my_file.write("Exam Completed\n")

my_file.close()

-- Standard Query Structure

SELECT first_name, score, class

FROM students

WHERE score >= 70 AND class = '11C'

ORDER BY score DESC;

-- Wildcard Search & Logical Conditions

WHERE surname LIKE 'Sm%' -- Starts with 'Sm'

WHERE email LIKE '%@aqa.org' -- Ends with domain

WHERE grade <> 9 -- Not equal (<> or !=)

-- Aggregate Functions (if tested)

SELECT COUNT(*), AVG(score), MAX(score) FROM results;