Basics

Question 1

Escape characters

Answer 1

Question 2

String literals can span multiple lines.

Answer 2

One way is using triple-quotes: “"”…””” or ‘'’…’’’. End of lines are automatically included in the string, but it’s possible to prevent this by adding a \ at the end of the line. The following example:

Question 3

Concatination and repeats

Answer 3

the + operator, and repeated with *

Question 4

String indexing

Answer 4

Question 5

String slicing

Answer 5

Question 6

One way to remember how slices work is to think of the indices as pointing . . .

Answer 6

Question 7

String immutability

Answer 7

Question 8

Lists

Answer 8

Question 9

Indexing and Slicing lists

Answer 9

Question 10

Slicing lists

Answer 10

Question 11

Concatinating lists

Answer 11

Question 12

List mutability

Answer 12

Question 13

len()

Answer 13

Question 14

Nesting Lists

Answer 14

Question 15

print()

Answer 15

Question 16

end

Answer 16

Question 17

multiple assignment

Answer 17

a, b = 0, 1

The variables a and b simultaneously get the new values 0 and 1. On the last line this is used again, demonstrating that the expressions on the right-hand side are all evaluated first before any of the assignments take place. The right-hand side expressions are evaluated from the left to the right.

Question 18

if Statements

Answer 18

Question 19

for Statements

Answer 19

Question 20

the range() function

Answer 20

Question 21

To iterate over elements in a range . . .

Answer 21

Question 22

A strange thing happens if you just print a range:

Answer 22

Question 23

the break statement

Answer 23

Question 24

the continue statement

Answer 24

Question 25

pass statements

Answer 25

Question 26

Defining functions: def

Answer 26

The keyword def introduces a function definition. It must be followed by the function name and the parenthesized list of formal parameters. The statements that form the body of the function start at the next line, and must be indented.

The first statement of the function body can optionally be a string literal; this string literal is the function’s documentation string, or docstring. (More about docstrings can be found in the section Documentation Strings.) There are tools which use docstrings to automatically produce online or printed documentation, or to let the user interactively browse through code; it’s good practice to include docstrings in code that you write, so make a habit of it.

Question 27

Functin execution

Answer 27

The execution of a function introduces a new symbol table used for the local variables of the function. More precisely, all variable assignments in a function store the value in the local symbol table; whereas variable references first look in the local symbol table, then in the local symbol tables of enclosing functions, then in the global symbol table, and finally in the table of built-in names. Thus, global variables and variables of enclosing functions cannot be directly assigned a value within a function (unless, for global variables, named in a global statement, or, for variables of enclosing functions, named in a nonlocal statement), although they may be referenced.

Question 28

parameters (arguments)

Answer 28

The actual parameters (arguments) to a function call are introduced in the local symbol table of the called function when it is called; thus, arguments are passed using call by value (where the value is always an object reference, not the value of the object). 1 When a function calls another function, a new local symbol table is created for that call.

Question 29

re-naming mechanism

Answer 29

Question 30

It is simple to write a function that returns a list of the numbers of the Fibonacci series, instead of printing it:

Answer 30