Lecture 3: Data Types, Input/Output, and Basic Functions

Vocabulary flashcards covering data types, input/output, type conversions, and basic functions from Lecture 3.

Type (in programming)

The kind of data stored in a variable that determines how the data is interpreted.

Integer

A whole number that can be positive or negative; has no decimal component.

Floating-Point Number

A real number with a decimal component; represented using mantissa and exponent.

Mantissa

The significant digits of a floating-point number before applying the exponent.

Exponent

The power of ten used to scale a mantissa in a floating-point number.

Boolean

A value that is either True or False used in logical decisions.

String

A sequence of characters used to represent text; defined in quotes.

Quotation marks in strings

Strings can use single or double quotes; the other type can be included via escaping.

Escape character

Backslash used to introduce special characters inside strings.

Triple-quoted string

String enclosed by three consecutive quotes; can span multiple lines and include both quote types.

Backslash escape sequences

Escape sequences introduced by a backslash to represent special characters such as tab, newlines, or quotes.

Forward slash

Symbol used for division in many languages.

Type inference

Python infers a variable's type from how it is created or last assigned.

Explicit typing

Declaring a variable's type directly in languages that require it (not typically needed in Python).

print()

Output values to the console; by default ends with a newline.

input()

Read a line from standard input as a string.

Literal

A fixed value written directly in code (e.g., 3, 'text').

Concatenation

Joining two strings with the plus operator to form a new string.

Addition vs concatenation

• adds numbers; for strings, + concatenates.

Repetition (string)

Multiplying a string by an integer repeats the string.

Converting between types

Changing a value's type using constructors like int(), float(), str(), bool().

int()

Convert a value to integer; decimals are truncated.

float()

Convert a value to floating-point; decimals are preserved.

str()

Convert a value to its string representation.

bool()

Convert a value to boolean; falsey values become False, others True.

Converting from strings to numbers

Strings that clearly represent a number can be converted with int() or float().

int('3')

Converts the string '3' to the integer 3.

float('3.14')

Converts the string '3.14' to the floating-point number 3.14.

repr vs str

repr returns the formal representation used for debugging; str returns a readable, user-friendly form.

print with multiple values

The print function can output several items if given more than one argument; they are separated by spaces by default.

sep and end in print

sep defines the between-item separator; end defines what is printed at the end.

f-strings

Formatted string literals that embed expressions inside braces after prefix f.

Format specifier in f-strings

Inside placeholders, after colon you can specify format like .4f to control precision.

Alignment in f-strings

Input prompt

The string passed to input is printed as a prompt before reading input; no automatic newline after the prompt.

from math import *

Import statement to bring all names from the math module into the namespace (e.g., pi).

def function

The keyword to define a function; followed by name, parameters, colon, and indentation for the body.

Parameters vs Arguments

Parameters are the names in a function definition; arguments are the values supplied when calling.

Return value

The value produced by a function via the return statement.

Indentation

Python uses indentation to define code blocks; typically 4 spaces.