6 Defining Functions

Question 1

How to import all the functions in a library?

Answer 1

from function import *

Question 2

What are the two drawbacks of not using functions?

Answer 2

having to write the code twice, the same code has to be maintained at two different places

Question 3

What is “a function definition”?

Answer 3

A part of the program to creates a function

Question 4

What does it mean for a function to be “called” or “invoked”?

Answer 4

The function is used in a program

Question 5

What is “the scope of a variable”?

Answer 5

Refers to the places in a program where a given variable may be referenced

Question 6

Discuss the scope of variables used inside a function.

Answer 6

They are local to that function.

Question 7

What is only way for a function to see a variable from another function?

Answer 7

Passing the variable as a parameter

Question 8

How does “a function definition” look like?

Answer 8

def ():

Question 9

What are “formal parameters”?

Answer 9

They are variables only accessible in the function body (subset of local variables).

Question 10

How to call a function?

Answer 10

()

Question 11

What happens after a function call (five steps)?

Answer 11

(1. Calling program suspends execution.)(2. Function definition is looked up.)(3. Formal parameters get assigned by values of actual parameters.)(4. The function body is executed.)(5. Control returns to the point of function call.)

Question 12

How are formal and actual parameters matched?

Answer 12

By position

Question 13

How to use “keyword parameters”?

Answer 13

def ( = ): , ( = ), match my name

Question 14

Where do fundamental ideas and vocab for functions come from?

Answer 14

From mathematical functions

Question 15

What two things happen after control reaches “return” statement?

Answer 15

(1. exits and returns to the point of function call.)(2. The value provided in the return statement is sent back to caller.)

Question 16

In what form is the value in return statement returned to caller?

Answer 16

As expression

Question 17

Why are value-returning functions extremely useful?

Answer 17

They are more elegant and flexible.

Question 18

How to print in a file?

Answer 18

(outf = open(‘something.txt’, ‘w’))(print(something, file=outf))(outf.close()

Question 19

How to return more than one value?

Answer 19

return ,

Question 20

How to achieve simultaneous assignment?

Answer 20

, = return ,

Question 21

What do “functions without a return” return?

Answer 21

None

Question 22

What is the main way to send information from a function back to its caller?

Answer 22

Return values

Question 23

Does the called function have access to the variable that holds the actual parameter?

Answer 23

No. The formal parameter only receive the values of actual parameters.

Question 24

Does python pass all parameter by value?

Answer 24

Yes

Question 25

Why can lists be changed inside a function?

Answer 25

Because a list is mutable, that is, it is only the vehicle to values, not the actual values themselves

Question 26

Why are functions used even when they sometimes make programs longer?

Answer 26

Because they make programs more modular.