Functions, Tuples, Dictionaries, Exceptions, and Data Processing

Question 1

What is decomposition?

Answer 1

Dividing he code into well-isolated pieces and encodes each of them in the form of a function

Question 2

What are the two conditions of creating a function?

Answer 2

• if a particular fragment of code is repeated in more than one place
• if a piece of code is so large that reading and understanding it may cause problems, split into smaller problems and implement each in form of function

Question 3

Where do functions come from ?

Answer 3

python
modules
code

Question 4

What are the two important catches of functions?

Answer 4

You mustn’t invoke a function which is not known at the moment of invocation

You mustn’t have a function and a variable of the same name.

Question 5

What makes parameters different to variables?

Answer 5

parameters exist only inside functions in which they have been defined, and the only place where the parameter can be defined is a space between a pair of parentheses in the def statement;
assigning a value to the parameter is done at the time of the function’s invocation, by specifying the corresponding argument.

Question 6

What is the difference between an argument and a parameter?

Answer 6

parameters live inside functions (this is their natural environment)
arguments exist outside functions, and are carriers of values passed to corresponding parameters.

Question 7

What is shadowing?

Answer 7

When a variable has the same name as a parameter

(parameter is define only inside the function)

Question 8

What is positional parameter passing?

Answer 8

A technique which assigns the nth argument to the nth function parameter is called positional parameter passing, while arguments passed in this way are named positional arguments.

Question 9

What is keyword argument passing?

Answer 9

The meaning of the argument is dictated by its name, not by its position

Question 10

What is the rule for mixing key word and positional argument passing?

Answer 10

you have to put positional arguments before keyword arguments

Question 11

What are two uses of None?

Answer 11

when you assign it to a variable (or return it as a function’s result)
when you compare it with a variable to diagnose its internal state.

Question 12

Is a variable created outside any function visible inside the functions?

Answer 12

YES, A variable existing outside a function has a scope inside the functions’ bodies, excluding those of them which define a variable of the same name.

Question 13

What does the global keyword do?

Answer 13

Extends a variable’s scope in a way which includes the functions’ bodies

In other words, this name becomes global (it has a global scope, and it doesn’t matter whether it’s the subject of read or assign).

Question 14

What is recursion?

Answer 14

recursion is a technique where a function invokes itself

Question 15

What is a sequence type?

Answer 15

a sequence is data which can be scanned by the for loop.

Question 16

What is mutability?

Answer 16

Mutable data can be freely updated at any time

Immutable data cannot be modified in this way.

Question 17

How do you create a one element tuple?

Answer 17

one_element_tuple_1 = (1, )
one_element_tuple_2 = 1.,

If you want to create a one-element tuple, you have to take into consideration the fact that, due to syntax reasons (a tuple has to be distinguishable from an ordinary, single value), you must end the value with a comma:

Question 18

Output of:

my_tuple = (1, 10, 100)
t1 = my_tuple + (1000,10000)

Answer 18

(1, 10, 100, 1000, 10000)

Question 19

Things to remember about dictionaries?

Answer 19

Keys must be unique
dictionary is a one way tool can look for values of keys but not keys of values
dictionaries don’t preserve the order of data as it is meaningless

Question 20

For loops for dictionaries?

Answer 20

for key, value in dictionary.items():

for key in dictionary.keys():

for value in dictionary.values():

Question 21

What happens if an error occurs between the try and except branches?

Answer 21

The program will not be terminated but it will jump to the except branch and no other part of the try will be executed

Question 22

Where must the default expect branch be?

Answer 22

At the end

Question 23

What is Zero division error?

Answer 23

when you try and divide by 0 using /, //, or %

Question 24

What are the types of exceptions?

Answer 24

ZeroDivisonError
ValueError
TypeError
AttributeError
SyntaxError

Question 25

Be careful: keywords cannot be used as variables/arguments!!!!!!

Question 26

What is a ValueError?

Answer 26

When a function receives an argument o a proper type but the value is unacceptable int(‘the’)

Question 27

What is a TypeError?

Answer 27

When you try to apply a data who’s type is cannot be accepted in the current context