python basics

Question 1

An algorithm and what is representaiton

and what are the steps of algorithm

Answer 1

that solves the problem by use of the
representation. A sequence of unambiguous
instructions for solving a problem, for obtaining a
required output for any legitimate input in a finite
amount of time.

that captures all the relevant
aspects of the problem.

design, analysis, planning, implementation,

Question 2

what is a complier and intrepreter

Answer 2

Compiler: Converts entire high-level language programs to machine language at once, takes less time
An error in code makes the whole compliation stop

Interpreter: Converts high-level language to machine language line by line and
execute instructions in place of CPU, if there is an error the code stops executing, takes more time to execute, interpreter gives a more detailed error message, and more accurate debugging

Question 3

binary system digits and decimal systems and hexadecimal, and coversion

Answer 3

0,1
0,1,2,3,4,5,6,7
0-9 (num is terms of binary)
10-15 in term of (A,C,D,E,F)=> binary of 10-15

binary => hexa
0-10 numbers,
binary to decimal (8421 method) hexa is base of 16

hexadecimal to decimal

Question 4

Main memory and secondary memoey

low level, middle level, high level

Answer 4

A Memory where currently executing
programs reside
It is volatile, the contents are lost
when the power is turned off.

Provides long-term storage of programs and data. Non-volatile, the contents are retained when power is turned off.

low level, middle, high level
directly understood by the machine. Much harder to code with, but has the fastest performance
Machine language

Middle level
provides some basic data structures and definitions while still
maintaining direct interaction with the machine. Still somewhat hard to code
with, but has fast performance. C, C++
High level
Focuses on ease of use and provides many programming structures
by default. Worse performance but very easy to code and develop with. Python, JavaScript

Question 5

What is docstring?

Answer 5

special type of comment
(“”” or ‘’’)

Question 6

what is a syntax and what is a semantics error and which will show error in complier

Answer 6

a set of characters and the acceptable sequences
(arrangements) of those characters.

a type of logic error in computer programming that occurs when a program’s meaning is incorrect:
But program runs successfully

only syntax errors will displayed on compliers

Question 7

Characteristics of print function

Answer 7

Can display/print anything in the world.
* Can take any type of arguments.
Values could be Numbers, Boolean, strings, collections, expressions, functions,
etc.
* Can take any number of arguments.
* Has the capability to evaluate the expression.
* Formatting is possible to some extent using the keyword separators – sep & end

Question 7

what is the code to change the separation from (space) to :

And what is sep

And what is end function
and what removes next like using end

Answer 7

print(10,12,14, sep = “:”)
10:12:14

string inserted between values, default a space.

end function
string appended after the last value, default a newline or in this case all numbers are in the same line
print() can be used here

print(10,12,14, end = “ ”)
print(16,18)
10 12 14
16 18

Question 7

variable rules

Answer 7

• can begin with a-z or A-Z. not with numbers
• 0-9 or a special character and Quotes are not allowed.
• Spaces are not allowed as part of an identifier
• underscores are allowed but but we do not prefer to use _ as the first character as it it has a special
  meaning.
  no special characters allowed
• can only contain alpha numeric characters and underscores

Question 8

what does an id() do

what is the function ‘‘is’’

Answer 8

returns the identity of an
object: like a serial number

Commonly used to check if two variables or objects are similar

function is

The is keyword is used to test whether two
variables belong to the same object.

The test will return True if the two objects are the same else it
will return False

Question 9

what is a datatype and what is the significance and what is function that returns the type of the object

what are relational operators and example

Answer 9

Memory associated with it
Operations that can be performed on it.
Range of values allowed in it

type(object)

relational operators

Relational expressions are a type of Boolean expression, since they evaluate
to a Boolean result

3 > 2 > 1
(3>2) and (2>1)

Question 9

what is Truncation Division and symbol left and right division

boolean logical operators: false and true

Membership operator (in and not in)

Answer 9

// (coverts decimal point into whole number)

operands can be both integer and floating points

ex: 5//2 = 2
5//2.0=2.0

left right division will return the answer in float or one decimal place

boolean false and true

False Values: 0 , ‘’ (Empty String), [] , {} , ()

True Values: Values: non – Zero numbers numbers , Non Empty String

Membership operator

membership operators can also be used to check if a given string occurs
within another string

> ‘E’ in ‘PES’ => true
‘F’ not in ‘PES => false

Question 10

Bitwise operations &, |, ^, «,», ~ ,%
and meaning

Answer 10

characters that perform actions on data at the bit level, or binary level

AND, OR| (if val is 0 other value is considered true),
^ Exclusive OR: result is 1 if and only if one of the bits is 1
&laquo_space;
LEFT SHIFT, multiply by 2^n for each left shift
» (ans=number of 1s on the binary)
RIGHT SHIFT divide by 2 for each right shift
~
ONE’S COMPLIMENT change 0 to 1 and 1 to 0
-(n +
% Check if the least significant bit is 1 (odd number)

print(var)

Question 11

what is addition, subtraction, multiplication, division in bitwise function, division, modulus, Exponentiation in bitwise function

Answer 11

a += b
a = a + b

a -= b
a = a - b

a *= b
a = a * b

a /= b => floating point
a = a / b ex 4.0

a //= b
a = a //b

a %= b (division, modulus, Exponentiation in bitwise function)
a = a % b
a **= b
a = a ** b

Question 12

what is the order precedence

what is operator associativity and the exception

Boolean logical operators (Short Circuit Evaluation)

Answer 12

it follows PEMDAS, for ex multiplication has more preference than addition

Operator associativity
Operators in the same box group left to right

Operators in the same box group left to right (except for exponentiation, which groups
from right to left).
Ex: 2 ** (3 ** 2) # 2 ** 9 = 512

Solve ans 3
result = 2 + 3 * 4 ** 2 / 8 - 5
print(result)

Boolean short circuit

logical and: if the first operand evaluates to false, then regardless of the value of the
second operand, operand, the expression expression is false

logical or: if the first operand evaluates to true, regardless of the value of the second operand, the expression is true.

Question 13

what is selection control and iterative control
sequential control

Answer 13

also known as Decision control statements or branching
statements.

The selection statement allows a program to test several conditions and execute

The set of statements following a header in Python is called a suite

The statements of a given suite must all be indented the same amount

some examples: If, if-else,if-elif-else

iterative control

• A control statement providing the repeated execution of a set of instructions
  aka loops

Sequential control

Sequential statements are a set of statements whose execution process happens
in a sequence

Question 13

while loop
valid indentation

Answer 13

• Repeatedly executes a set of statements based on the provided expression (condition).
  As long as the condition of a while statement is true, the statements within the loop are (re)executed (re)executed.
• Once the condition becomes false, the iteration terminates and control continues withthe first statement after the while loop

idealy 4 spaces should be present but both if and else statements spacing must match
and spacing must match adajcent statements

Question 14

what is ord and char

how to print random numbers

range(4,0) correct

what are some basic errors they will ask you about

is there any limit on size of int

Answer 14

SyntaxError

ord gives ASCII value and char converts ASCII to char

import random
random.randrange()

only has ascending, not descending if range(4,0), it must have range(4,0,-1)
decrements also

ERRORS

print(x)
NameError => name ‘x’ is not defined

#IndentationError
print(x+y)
#TypeError
data types
#ValueError

limit on size of int

There is no practical limit to the size of an integer in Python.

Question 15

pyramid structure code

Answer 15

for i in range(4,0,-1): # Loop starts from 4, goes down to 1
for j in range(i, 5): # Inner loop starts at ‘i’ and ends at 4
print(j, end=” “) # Print each number in the row
print() # Move to the next line after each row

Question 16

how to reverse list

type casting

Which of the following operators has the lowest precedence?

not
%
and
**

Answer 16

[::-1]:

The expression (float) 2 + 4.5 is an example of type casting (also known as type conversion), specifically explicit type casting.

following operators has the lowest precedence

and has the lowest precedence.

Question 17

What are the advantages and limitations in python?

brute force approach and
what is limits of computational problem solving

Answer 17

Ease of Learning and Use, Python is used in a wide range of fields,

DIS:
Slower Execution Speed,Python is known to use more memory

BRUTE FORCE

A brute force approach is a straightforward problem-solving technique where all possible solutions or combinations are tried until the correct one is found.

Time and space required grow with input size. Some problems (e.g., NP-hard) are infeasible to solve for large inputs.

Question 18

what is literal?

Answer 18

A literal in programming is a fixed value that is directly written into the code, representing a constant value of a specific type. Literals are used to assign values to variables or as direct values in expressions.

and types of literals

Integer literal
floating-point literal
boolean literal
string literal
none literal
complex literal