Data Representation in Python

Question 1

How can an integer in python be represented as binary, octal, hexadecimal

Answer 1

:
{num}
{num : b}
{num : x}
{num : o}

Question 2

How can you store integers using different bases

Answer 2

using prefixes
[19, 0b1010, 0xf35, 0o17]

all stored as integers NOT strings

Question 3

what displays the maximum number of digits
that can be stored in an integer object under a specific system.

Answer 3

sys.get_int_max_str_digits()

Question 4

how to convert 0b11101 into float

Answer 4

float(0b11101) -> 29.0

Question 5

There is a limitation to the maximum number that can be stored in a float object. This can
be retrieved using

Answer 5

sys.float_info

Question 6

how is infinity and - infinity represented in python

Answer 6

float(‘inf’) and float(‘-inf’)

no infinite object for integers

Question 7

If a string contains all numerical characters, then it can be converted into an integer, using
the command

Answer 7

int(val) for decimal otherwise specify base

int(‘0b110111’,2) → 55
int(‘0xf35’,16) → 3893
int(‘0o17’,8) → 15

Question 8

float(‘0b110111’,2)
float(‘0xf35’,16)
float(‘0o17’,8)
output?

Answer 8

TypeError

Question 9

Output of
int(‘34bc1’)
float(‘34/2’)

Answer 9

ValueError exception

Question 10

What functions are used to
convert any integer into a string using the appropriate base.

Answer 10

bin()
hex()
oct()

Question 11

To create a bytes object, we can use three different methods:

Answer 11

using a string with b’ ‘

using bytes() command w/ number of bytes

using bytes() w/ string and encoding

Question 12

for the first method of byte representation
b’ ‘
what should the characters be

Answer 12

characters must be ASCII
for non-printable use hexadecimal format like b’\x15st’

if you provide the entire string in hex it would only convert printable characters

Question 13

list encoding types

Answer 13

‘ascii’
‘utf-8’
‘utf-16’
‘utf-32’

Question 14

x = b’ab’
y = [i for i in x] → [97,98]
list(x) → [97,98]

is this valid ?

Answer 14

yes bytes data type is iterable and sub-scriptable
However immutable
can’t do x[0] = b’z’

Question 15

What if I want a mutable bytes?

Answer 15

use bytearray data type

Question 16

There are two ways in which computer machines store sequence of bytes

Answer 16

little (host order) and big endian (network order)

Question 17

To figure out the byte order in your machine, use the Python command:

Answer 17

print(sys.byteorder)

Question 18

For instance, the byte sequence: b’\x61\x62\x63\x64’,
equivalent to b’abcd’, is stored as:

Answer 18

b’\x61\x62\x63\x64’(big endian)
b’\x64\x63\x62\x61’ (little endian)

Question 18

Converting From Integers to Bytes:

Answer 18

(int obj).to_bytes(#bytes, byteorder)

Question 18

How to convert from bytes to an integer

Answer 18

int.from_bytes(bytes, byteorder)

Question 18

Description of ascii encoding

Answer 18

characters are stored in a single byte (fixed length). Only the least 7 bits are used
the first 32 characters are non-printable and for control only

Question 19

UTF-8 description

Answer 19

characters are stored in
1, 2, 3 or 4 bytes
(var length system) used in 95% of websites
compatible with ASCII

Question 20

utf-16 description

Answer 20

characters are stored in 2 or 4 bytes
(variable length system)
MS API and java

Question 21

utf-32 description

Answer 21

characters are stored in 4 bytes (fixed length system)
used by internal APIs in some progslangs and few UNIX programs

Question 22

what are the ord and chr functions

Answer 22

built-in functions to convert characters to their encoding values ord takes single unicode characters and returns an integer value chr takes an integer and returns corresponding unicode character English two digit number int Arabic four digit number int

Question 23

Python allows the use of Unicode characters as numbers using what prefix

Answer 23

'\u' por ejemplo x = '\u0061' x = '\u0100'

Question 24

what does x.hex() knowing x is a bytes object

Answer 24

This method acts like the hexlify function except that the return value is a string.

Question 25

what function returns the Unicode number representation corresponding to each character, stored in a bytes object.

Answer 25

hexlify (b'a') -> b'61' hexlify(b'ab') -> b'6162'

Question 26

The reverse process where you get the encoding number and you want the character stored in a bytes object

Answer 26

unhexlify(b'61') -> b'a'

Question 27

in which library do we have hexlify and unhexlify

Answer 27

binascii

Question 28

Convert a 32-bit positive integer from host to network byte orde

Answer 28

htonl(x)

Question 29

Convert 32-bit positive integers from network to host byte order

Answer 29

ntohl(x)

Question 30

Convert 16-bit positive integers from host to network byte order

Answer 30

htons(x)

Question 31

Convert 16-bit positive integers from network to host byte order

Answer 31

ntohs(x)

Question 32

Convert an IPv4 address2 from a four dot-string IP format into a binary format

Answer 32

inet_aton(ip_string)

Question 33

Convert an IPv4 address from a binary format into a four dot-string IP format

Answer 33

inet_ntoa(ip_string)