Chapter 9 (functions)

Question 1

what can be used to check for global and local variables?

Answer 1

globals()
locals()
- These variables act as dictionaries that store the key (variable name) with its value (assigned data to the variable)

Question 2

What is variable scope?

Answer 2

How accessible a variable is to sections of code:
- if a variable is local, it can only be accessed within the function, if it is global it can be accessed anywhere in the code

Question 3

What are the 3 types of scope?

Answer 3

Built-in scope:
- can be accessed anywhere with no restrictions, they are the built-in names of python: str(), int(), etc.
Global scope:
- variables that have been declared outside of functions
Local scope:
- only accessible in a function

Question 4

In what order are variables checked in a function?

Answer 4

• Local
• Global
• Built-in

Question 5

What is namespace?

Answer 5

maps (like a dictionary) of names of objects in a given scope

Question 6

What is scope resolution?

Answer 6

The process of searching namespace for a name,
- looking for a variable in the dictionary of names

Question 7

How does python interpreter restrict variable scope?

Answer 7

assigning variables to a namespace

Question 8

Can the same name be in multiple namespaces?

Answer 8

Yes

Question 9

Will there be an error if I define a list as list() since it is already a built-in name?

Answer 9

No because it is going to be defined as a global or local variable which are read before the built-in names

Question 10

Can immutable objects be edited inside a function?

Answer 10

no, the object will not be edited, instead a new object will be made in the local scope of the function with the values assigned to it instead of editing the global variable

Question 11

Can mutable objects be edited inside a function?

Answer 11

Yes they can, for example a list or dictionary, however, only edited, not replaced.
- index overwriting is fine, but straight up changing the whole list all at once will not impact the list

Question 12

what would be the output of:
def modify(list):
‘’’ docstring ‘’’
list[1] = 99
my_list = [1,2,3]
modify(my_list[:])
print(my_list)

Answer 12

[1,2,3] because the argument is actually a copy of my_list not the real list

Question 13

When preassigning values to parameters, what must be true?

Answer 13

All parameters that have preassigned values must be in the correct order

Question 14

Can you put the arguments in any order when calling a function?

Answer 14

Sometimes, only when the parameter is specified = a value

Question 15

What is an arbitrary parameter?

Answer 15

When the number of parameters cannot be predicted, so the function excepts more than normal all stored in an arbitrary parameter

Question 16

What are some examples of arbitrary parameters?

Answer 16

*args (arguments)
**kwargs (key word arguments, stores a dictionary)

Question 16

What are some examples of arbitrary parameters?

Answer 16

*args (arguments)
**kwargs (key word arguments, stores a dictionary)

Question 17

Can a function return more than one object?

Answer 17

no, however a tuple of multiple values can be returned

Question 18

What does the follwing line do?
def f():
‘’’ docstring ‘’’
return val1,val2
val3, val4 = f()

Answer 18

val3 = val1
val4 = val2
val1 and val2 where returned in a tuple

Question 19

MUST INCLUDE DOC STRING OR -2 POINTS

Question 20

what does help(function) do?

Answer 20

Instead of running the function, it outputs the doc string

Question 21

How do you define a function?

Answer 21

def function():
‘’’ docstring ‘’’
return value

Question 22

How do you pass a create a function with a fixed value incase the variable is not passed?

Answer 22

def function(a, b=25):

Question 23

How do you selectively run code depending on if the file is being run as a main program or an imported module?

Answer 23

if __name__ = ‘__main__’:
—-code for regular file
code if file was imported as a module

Question 24

When returning a tuple from a function, how do you print an index from the tuple?

Answer 24

print(function(pass)[index])

Question 25

When setting a default value in a function, what must be true in terms of order?

Answer 25

The default values must be declared last

Question 26

What happens if there are two return statements in a function?

Answer 26

The first return statement that is encountered will end the function and return to the main code