Python

Question 1

Name the main Pandas features (5)

Answer 1

1) DataFrame object for data manipulation 2) Tools for reading and writing data. 3) time series-functionality 4) Provides data filtration 5) the library is highly optimized for performance with critical part written in cython or c.

Question 2

What is matplotlib?

Answer 2

Matplotlib is a Python 2D plotting library which produces publication quality figures in a variety of hardcopy formats and interactive environments across platforms.

Question 3

What is scikit-learn?

Answer 3

Scikit-learn is a free software maching learning library. It features various classification, regression and clustering algorithms.

Question 4

What is the OS module for?

Answer 4

The OS module in python provides functions for interacting with the operating system. OS, comes under Python’s standard utility modules. This module provides a portable way of using operating system dependent functionality. The *os* and *os.path* modules include many functions to interact with the file system.

Question 5

What is the sys module ?

Answer 5

The sys module provides functions and variables used to manipulate different parts of the Python runtime environment.

Question 6

What is the math module?

Answer 6

Some of the most popular mathematical functions are defined in the math module. These include trigonometric functions, representation functions, logarithmic functions, angle conversion functions, etc. π and e are also defined.

Question 7

What is the statistic module ? What are the function included ?

Answer 7

The statistics module provides functions to mathematical statistics of numeric data. The following popular statistical functions are defined in this module.

>>> import statistics
>>>statistics.mean([2,5,6,9])
5.5

>>>statistics.median([1,2,3,8,9])
3

>>>statistics.mode([2,5,3,2,8,3,9,4,2,5,6])
2

>>>statistics.stdev([1,1.5,2,2.5,3,3.5,4,4.5,5])
1.3693063937629153

Question 8

What is a module in python?

Answer 8

Any text file with the .py extension containing Python code is basically a module. Different Python objects such as functions, classes, variables, constants, etc., defined in one module can be made available to an interpreter session or another Python script by using the import statement.

A module is described by its attributes. The attributes of a module perform some tasks or contain some information.

Question 9

What is the random module ?

Answer 9

Functions in the random module depend on a pseudo-random number generator function random(), which generates a random float number between 0.0 and 1.0.

Question 10

What is a package ?

Answer 10

Physically, a package is actually a folder containing one or more module files.

This is a good tutorial

https://www.tutorialsteacher.com/python/python-package

Question 11

What are the types of errors in python?

Answer 11

This website contain a good list of more errors in python:

https://www.tutorialsteacher.com/python/error-types-in-python

1) Syntax error: When a certain statement is not in accordance with the prescribed usage.

2) Index error: is thrown when trying to access an item at an invalid index.

3) ModuleNotFoundError: is thrown when a module could not be found

4) KeyError: is thrown when a key is not found

5) ImportError: is thrown when a specified function can not be found

6) StopIteration: is thrown when the next() function goes beyond the iterator items.

7) TypeError: is thrown when an operation or function is applied to an object of an inappropriate type.

8) ValueError: is thrown when a function’s argument is of an inappropriate type

9) NameError: is thrown when an object could not be found.

10) ZeroDivisionError: is thrown when the second operator in the division is zero

Question 12

Which keyword python use to handle exception ?

Answer 12

statements in try block

Python uses try and except keywords to handle exceptions.

try :

except :

Question 13

What do we mean by object oriented programming?

Answer 13

Python is a completely object-oriented language. This approach towards programming seeks to treat data and functions as part of a single unit called object. The class defines attributes and the behaviour of the object, while the object, on the other hand, represents the class.

Question 14

How do we define a class in python ?

Answer 14

Using the keyword class. For example:

class person:

count=0 #class attribute

def __init__(self): #constructor

self. name=”unknown” #instance attribute
self. age=0 #instance attribute

def displayInfo(self): #method

print(self.name, self.age)

Question 15

What are the components (4) of a class in python?

Answer 15

1) Constructor: The constructor method is invoked automatically whenever a new object of a class is instantiated. The constructor must use __init__()
2) Instance Attributes: Attributes or properties attached to an instance of a class.
3) Class Attributes: An attribute whose value is the same for all instances of a class.
4) Methods: They are the function of the class.

Question 16

What are the 3 type of access modifier?

Answer 16

Public: The members of a class which are declared public are easily accessible from any part of the program. All data members and member functions of a class are public by default.

Protected: The members of a class which are declared protected are only accessible to a class derived from it. Data members of a class are declared protected by adding a single underscore ‘_’ symbol before the data member of that class.

Private: The members of a class which are declared private are accessible within the class only, private access modifier is the most secure access modifier. Data members of a class are declared private by adding a double underscore ‘__’ symbol before the data member of that class.