CSCI Midterm

How do you assign a value to a variable in Python?

Use variable_name = value.

Difference between int, float, and str?

int = whole numbers, float = decimals, str = text.

How do you concatenate two strings?

"hello" + "world".

What does input() do?

Reads user input and returns it as a string.

What does type() do?

Shows the data type of a value or variable.

Convert "25" to an integer.

int("25").

How do you write a comment in Python?

Use #.

Convert a string to lowercase.

s.lower().

How do you find the length of a string or list?

len().

What does len() return?

Number of items/characters.

What’s the purpose of an if-else statement?

To run different code depending on a condition.

What is elif used for?

Multiple conditions when if isn’t true.

Difference between and and or?

and: both conditions must be true; or: at least one must be true.

What does not do?

Reverses a Boolean value.

Structure of a while loop?

while condition: code.

How does a for loop work?

Iterates over items in a sequence (list, string, range).

Purpose of break?

Stops a loop immediately.

Purpose of continue?

Skips to the next loop iteration.

Print numbers 1–10 using a loop.

for i in range(1, 11): print(i).

Difference between list and dictionary?

List uses indexes; dictionary uses key-value pairs.

Create an empty list.

[] or list().

Append to a list.

lst.append(item).

Remove last item in a list.

lst.pop().

Access first list element.

lst[0].

Access last list element.

lst[-1].

Reverse a list using slicing.

lst[::-1].

Add an item to a dictionary.

d[key] = value.

Check if value exists in list.

value in lst.

Combine lists.

list1 + list2.

Check if string contains substring.

"cat" in s.

Count vowels in a string (core idea).

Loop through characters and count "aeiou".

Split string into words.

s.split().

Remove whitespace on ends.

s.strip().

Reverse a string.

s[::-1].

What does find() do?

Returns index of substring or -1 if not found.

Replace substring.

s.replace("old", "new").

Convert to uppercase.

s.upper().

Check if string is numeric.

s.isdigit().

Format a string.

f"Hello {name}".

Purpose of return?

Sends a value back from a function.

How to define a function?

def function_name(params): code.

Function that returns sum of two numbers.

def add(a, b): return a + b.

Function that takes list and returns average.

sum / length.

What is an algorithm?

Step-by-step process to solve a problem.

Find minimum in a list?

Loop through, track smallest so far.

Sum elements in a list?

Use sum(lst) or loop and add.

Convert Celsius → Fahrenheit.

F = C * 9/5 + 32.

What is a local variable?

A variable created inside a function.

Number of parameters in def t(a,b,c,d)?

4.

How does binary search work?

Repeatedly splits sorted list in half to find a target.

What happens if list is not sorted?

Binary search fails / returns incorrect results.

How does insertion sort work?

Builds sorted list one element at a time by inserting into correct position.

Why sort a list?

Makes searching faster, organizes data.

Alternatives to insertion sort?

Bubble sort, Selection sort, Merge sort, Quick sort.