1) What is Python?
Ans)Python is a high-level, interpreted, interactive and object-oriented scripting language. Python is designed to be highly readable. It uses English keywords frequently where as other languages use punctuation, and it has fewer syntactical constructions than other languages.
2) What is the purpose of PYTHONPATH environment variable?
Ans) PYTHONPATH − It has a role similar to PATH. This variable tells the Python interpreter where to locate the module files imported into a program. It should include the Python source library directory and the directories containing Python source code. PYTHONPATH is sometimes preset by the Python installer
3)What are the supported data types in Python?
Ans)Python has five standard data types −
4)What are the key features of Python?
Ans) If it makes for an introductory language to programming, Python must mean something. These are its qualities:
5)Differentiate between deep and shallow copy.
Ans)A deep copy copies an object into another. This means that if you make a change to a copy of an object, it won’t affect the original object. In Python, we use the function deepcopy() for this, and we import the module copy. We use it like:
6)Explain the ternary operator in Python.
7)How is multithreading achieved in Python?
Ans) A thread is a lightweight process, and multithreading allows us to execute multiple threads at once. As you know, Python is a multithreaded language. It has a multi-threading package. The GIL (Global Interpreter Lock) ensures that a single thread executes at a time. A thread holds the GIL and does a little work before passing it on to the next thread. This makes for an illusion of parallel execution. But in reality, it is just threads taking turns at the CPU. Of course, all the passing around adds overhead to the execution.
Ans) When one class inherits from another, it is said to be the child/derived/sub class inheriting from the parent/base/super class. It inherits/gains all members (attributes and methods). Inheritance lets us reuse our code, and also makes it easier to create and maintain applications. Python supports the following kinds of inheritance:
9)What is Flask?
Ans) Flask, as we’ve previously discussed, is a web microframework for Python. It is based on the ‘Werkzeug, Jinja 2 and good intentions’ BSD license. Two of its dependencies are Werkzeug and Jinja2. This means it has around no dependencies on external libraries. Due to this, we can call it a light framework. A session uses a signed cookie to allow for the user to look at and modify session contents. It will remember information from one request to another. However, to modify a session, the user must have the secret key Flask.secret_key.
10) Explain help() and dir() functions in Python.
11)How is memory managed in Python?
Ans) Python has a private heap space to hold all objects and data structures. Being programmers, we cannot access it; it is the interpreter that manages it. But with the core API, we can access some tools. The Python memory manager controls the allocation. Additionally, an inbuilt garbage collector recycles all unused memory so it can make it available to the heap space.
12)Whenever you exit Python, is all memory de-allocated?
13) What is a dictionary in Python?
14)What do you mean by *args and **kwargs?
15) Write Python logic to count the number of capital letters in a file.
16)What are negative indices?
17) How would you randomize the contents of a list in-place?
18) Explain join() and split() in Python.
19) Explain split(), sub(), subn() methods of “re” module in Python.
20) What is pickling and unpickling?
Ans)Pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using dump function, this process is called pickling. While the process of retrieving original Python objects from the stored string representation is called unpickling.
21) Mention the differences between Django, Pyramid and Flask.
22)List out the inheritance styles in Django.
Ans) In Django, there is three possible inheritance styles:
23)How To Save An Image Locally Using Python Whose URL Address I Already Know?
Ans)We will use the following code to save an image locally from an URL address
24)What is map function in Python?
Ans)map function executes the function given as the first argument on all the elements of the iterable given as the second argument. If the function given takes in more than 1 arguments, then many iterables are given. #Follow the link to know more similar functions.
25)How to get indices of N maximum values in a NumPy array?
Ans)We can get the indices of N maximum values in a NumPy array using the below code:
import numpy as np
arr = np.array([1, 3, 2, 4, 5])
27)Explain the use of decorators.
28)How do you make 3D plots/visualizations using NumPy/SciPy?
29) Why are local variable names beginning with an underscore discouraged?
Ans)a) they are used to indicate a private variables of a class
b) they confuse the interpreter
c) they are used to indicate global variables
d) they slow down execution
30)What is the output of print list if list = [ 'abcd', 786 , 2.23, 'john', 70.2 ]?
31)What are tuples in Python?
Ans) A tuple is another sequence data type that is similar to the list. A tuple consists of a number of values separated by commas. Unlike lists, however, tuples are enclosed within parentheses.
32) What is the difference between tuples and lists in Python?
Ans) The main differences between lists and tuples are − Lists are enclosed in brackets ( [ ] ) and their elements and size can be changed, while tuples are enclosed in parentheses ( ( ) ) and cannot be updated. Tuples can be thought of as read-only lists.
33)How will you create a dictionary in python?
34)How will you get all the keys from the dictionary?
35)How will you convert a string to an int in python?
Ans) int(x [,base]) − Converts x to an integer. base specifies the base if x is a string.
36)How will you convert a object to a regular expression in python?
Ans) repr(x) − Converts object x to an expression string.
37)How will you create a dictionary using tuples in python?
38)What is the purpose of ** operator?
39) What is the purpose break statement in python?
Ans)break statement − Terminates the loop statement and transfers execution to the statement immediately following the loop.
41)What is the purpose pass statement in python?
Ans)pass statement − The pass statement in Python is used when a statement is required syntactically but you do not want any command or code to execute.
42)How will you randomizes the items of a list in place?
Ans)shuffle(lst) − Randomizes the items of a list in place. Returns None.
43)How will you get a space-padded string with the original string left-justified to a total of width columns?
Ans) ljust(width[, fillchar]) − Returns a space-padded string with the original string left-justified to a total of width columns.
44)What is the purpose of PYTHONCASEOK environment variable?
Ans) PYTHONCASEOK − It is used in Windows to instruct Python to find the first case-insensitive match in an import statement. Set this variable to any value to activate it.
45)What is the purpose of is operator?
Ans) is − Evaluates to true if the variables on either side of the operator point to the same object and false otherwise. x is y, here is results in 1 if id(x) equals id(y).
46)How will you sort a list?
Ans)list.sort([func]) − Sorts objects of list, use compare func if given.
47)When is pass used for?
Ans) :pass does nothing. It is used for completing the code where we need something. For eg:
48)What is the difference between a tuple and a list?
49)What is the output of [1, 2, 3] + [4, 5, 6]?
Ans) [1, 2, 3, 4, 5, 6]
50)How will you remove all leading whitespace in string?
Ans) strip() − Removes all leading whitespace in string.