Functions

Question 1

Arguments

Answer 1

positional *args
keyword **kwargs

variable-length (varargs):
*args, **kwargs

actual parameters

Question 2

Parameters

Answer 2

(pos, /, pos_or_kw, *, kw)

required
optional

formal parameters

PEP 570

Question 3

Parameters order

Answer 3

non-default parameters, default parameters

Question 4

Arguments order

Answer 4

positional, keyword

Question 5

Lambda

Answer 5

bound variable
single expression
no type annotations

argument to higher-order function

Question 6

Global Scope

Answer 6

global variable
global keyword
module scope

global variables are available from any scope except built-in

Question 7

Local Scope

Answer 7

declared inside function
available within the function

Question 8

Nonlocal Variable

Answer 8

nonlocal keyword
used in nested functions

defined in an outer (enclosing) scope but not in the global scope

Question 9

Enclosing Scope

Answer 9

scope of outer function

nonlocal scope

Question 10

Built-in Scope

Answer 10

special reserved keywords

__builtins__ module

Question 11

LEGB

Answer 11

Local
Enclosing
Global
Built-in

Question 12

First-Class Function

Answer 12

• assign to variable
• pass as an argument
• return from function

first-class citizen

Question 13

Higher-Order Function

Answer 13

a function that can take other functions as arguments or return functions as results

map, filter

Question 14

Free Variable

Answer 14

variable that is used in a code block but not defined there

in closure defined in enclosing scope

can be global if the nearest enclosing scope contains a global statement

can be nonlocal

Question 15

Closure

Answer 15

function that retains access to variables from the enclosing scope even after the outer function has finished executing

function.__closure__

closure factory

Question 16

Decorator

Answer 16

def decorator(func):
    def wrapper(*args, **kwargs):
        ...
        result = func(*args, **kwargs)
        ...
        return result
    return wrapper

@functools.wraps(func)

Question 17

Pie-Decorator

Answer 17

@decorator
def func:
    ...

func = decorator(func)

Question 18

Decorator with optional arguments

Answer 18

def name(_func=None, *, key1=value1, key2=value2, ...):
    def decorator_name(func):
        ...
    if _func is None:
        return decorator_name
    else:
        return decorator_name(_func)

Question 19

Top-level code

Answer 19

first user-specified module that starts running

__name__ == ‘__main__’

entry point

Question 20

Decorator with arguments

Answer 20

def name(args):
    def decorator_name(func):
        ...
    return decorator_name