\nSo, let’s start exploring Questions for Python Interview.
\nLet’s first revise the Python Tutorial<\/strong><\/a>.<\/p>\n
![\"Questions](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/09\/Python-Interview-Questions-1-01.jpg\")
<\/a>Questions for Python Interview – Guide To Crack Interview<\/p><\/div>\n
2. Tricky Questions for Python Interview<\/h2>\n
Following are the Practical Questions for Python Interview, which will help you to boost your confidence. Let’s discuss these Questions for Python Interview in detail: Help on wrapper_descriptor:<\/strong> 4<\/span><\/strong> 1<\/strong> Q.4. How will you convert a list into a string?<\/strong> ‘one two three four five six seven’<\/strong> (2, 2)<\/strong> array([], dtype=float64)<\/strong><\/span><\/p>\n array([], shape=(0, 0), dtype=float64)<\/strong> {1, 2, 3, 4}<\/strong> (1, 2, 4)<\/strong><\/p>\n (2+4j)<\/strong><\/p>\n [2, 4, 9]<\/strong><\/p>\n {1: 1, 2: 2}<\/span><\/strong> [22, 68, 110, 89, 31, 12]<\/strong> Q.13. Can you explain the life cycle of a thread?<\/strong> Questions for Python Interview – Life Cycle of a Thread<\/p><\/div>\n Q.14. Below, we give you code to remove numbers smaller than 5 from the list nums. However, it does not work as expected. Can you point out the bug for us?<\/strong> [5, 10, 100, 9, 24]<\/strong><\/p>\n [5, 10, 100, 9, 24]<\/strong><\/p>\n [5, 10, 100, 9, 24]<\/strong> Here\u2019s the entire code, though-<\/span><\/p>\n (3, 2)<\/strong> ‘aaabbbcccdddeee’<\/strong><\/p>\n ‘aaabbbcccdddeee’<\/strong>
\nQ.1. Are these statements optimal? If not, optimize them.<\/strong>
\nword=\u2019word\u2019<\/b>
\nprint(word.__len__())<\/b>
\nAns.<\/strong> No, these are not optimal. Let\u2019s check the manual for this.<\/span><\/p>\n>>> help(str.__len__)<\/pre>\n
\n__len__(self, \/)<\/strong>
\n \u00a0\u00a0\u00a0Return len(self).<\/strong>
\n__len__ is a wrapper descriptor which in turn makes a call to len(). So why not skip the work and do just that instead?<\/strong>
\nThe optimal solution:<\/span><\/p>\n>>> word='word'\r\n>>> len(word)<\/pre>\n
\nQ.2. Have you heard of the yield<\/i> keyword in Python?<\/strong>
\nAns.<\/strong> Yes, I have. This keyword bears the ability to turn any function into a generator. Much like the standard <\/span>return<\/span><\/i> keyword, but returns a generator<\/strong><\/a> object. It is also true that one function may observe multiple <\/span>yield<\/span><\/i>s.<\/span><\/p>\n>>> def odds(n):\r\n odd=[i for i in range(n+1) if i%2!=0]\r\n for i in odd:\r\n yield i\r\n>>> for i in odds(8):\r\n print(i)<\/pre>\n
\n3<\/strong>
\n5<\/strong>
\n7<\/strong>
\nQ.3. How will you print the contents of a file?<\/strong>
\nAns.<\/strong><\/p>\n>>> try:\r\n with open('tabs.txt','r') as f:\r\n print(f.read())\r\nexcept IOError:\r\n print(\"File not found\")<\/pre>\n
\nAns.\u00a0<\/strong>We will use the join() method for this.<\/span><\/p>\n>>> nums=['one','two','three','four','five','six','seven']\r\n>>> s=' '.join(nums)\r\n>>> s<\/pre>\n
\nLet’s revise the Python string in detail<\/a><\/strong>
\nQ.5. What will the following code output?<\/strong>
\n>>> a=1<\/b>
\n>>> a,b=a+1,a+1<\/b>
\n>>> a,b<\/b>
\nAns.<\/strong> The output is (2, 2). This code increments the value of a by 1 and assigns it to both a and b. This is because this is a simultaneous declaration. The following code gives us the same:<\/span><\/p>\n>>> a=1\r\n>>> b,a=a+1,a+1\r\n>>> a,b<\/pre>\n
\nHave a look at Python Built-in Functions<\/a><\/strong>
\nQ.6. Explain different ways to create an empty NumPy array in Python.<\/strong>
\nAns.<\/strong> We\u2019ll talk about two methods to create NumPy<\/a><\/strong> array-<\/span><\/p>\n\n
>>> import numpy\r\n>>> numpy.array([])<\/pre>\n
\n
>>> numpy.empty(shape=(0,0))<\/pre>\n
\nQ.7. How will you remove a duplicate element from a list?<\/strong>
\nAns.<\/strong> We can turn it into a set to do that.<\/span><\/p>\n>>> list=[1,2,1,3,4,2]\r\n>>> set(list)<\/pre>\n
\nLet’s revise the Python\u00a0List<\/a><\/strong>
\nQ.8. How many types of objects does Python support?<\/strong>
\nAns. Objects in Python<\/a><\/strong> are mutable and immutable. Let\u2019s talk about these.<\/span><\/p>\n\n
>>> tuple=(1,2,4)\r\n>>> tuple<\/pre>\n
>>> 2+4j<\/pre>\n
\n
>>> [2,4,9]<\/pre>\n
>>> dict1={1:1,2:2}\r\n>>> dict1<\/pre>\n
\nWhile two equal immutable objects\u2019 reference variables share the same address, it is possible to create two mutable objects with the same content.<\/span>
\nQ.9. What is a control flow statement?<\/strong>
\nAns.<\/strong> A Python program usually starts to execute from the first line. From there, it moves through each statement just once and as soon as it\u2019s done with the last statement, it transactions the program. However, sometimes, we may want to take a more twisted path through the code. Control flow statements let us disturb the normal execution flow of a program and bend it to our will.<\/span>
\nQ.10. Create a new list to convert the following list of number strings to a list of numbers.<\/strong>
\nnums=[\u201822\u2019,\u201968\u2019,\u2019110\u2019,\u201989\u2019,\u201931\u2019,\u201912\u2019]<\/b>
\nAns.<\/strong> We will use the int() function with a list comprehension to convert these strings into integers and put them in a list.<\/span><\/p>\n>>> [int(i) for i in nums]<\/pre>\n
\nQuestions for Python Interview for freshers – Q. 2,3,6,7,8,9<\/strong>
\nQuestions for Python Interview for experienced – Q. 1,4,5,10<\/strong>
\nQ.11. What is the MRO in Python?<\/strong>
\nAns. MRO stands for Method Resolution Order<\/a><\/strong>. Talking of multiple inheritances, whenever we search for an attribute in a class, Python first searches in the current class. If found, its search is satiated. If not, it moves to the parent class. It follows an approach that is left-to-right and depth-first. It goes Child, Mother, Father, Object.<\/span>
\nWe can call this order a linearization of the class Child; the set of rules applied are the Method Resolution Order (MRO). We can borrow the __mro__ attribute or the mro() method to get this.<\/span>
\nQ.12. Are methods and constructors the same thing?<\/strong>
\nAns.<\/strong> No, there are subtle but considerable differences-<\/span><\/p>\n\n
\nLet’s revise Python Multithreading<\/a><\/strong><\/p>\n\n
![\"Questions](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/09\/thread-life-cycle.jpg\")
<\/a>
\n>>> nums=[1,2,5,10,3,100,9,24]<\/b>
\n>>> for i in nums:<\/b>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0if i<5:<\/b>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0nums.remove(i)<\/b>
\n>>> nums<\/b>
\n[2, 5, 10, 100, 9, 24]<\/b>
\nAns.<\/strong> This code checks for each element in nums- is it smaller than 5? If it is, it removes that element. In the first iteration, 1 indeed is smaller than 5. So it removes that from this list. But this disturbs the indices. Hence, it checks the element 5, but not the element 2. For this situation, we have three workarounds:<\/span><\/p>\n\n
>>> nums=[1,2,5,10,3,100,9,24]\r\n>>> newnums=[]\r\n>>> for i in nums:\r\n if i>=5:\r\n newnums.append(i)\r\n>>> newnums<\/pre>\n
\n
>>> nums=[1,2,5,10,3,100,9,24]\r\n>>> newnums=[i for i in nums if i>=5]\r\n>>> newnums<\/pre>\n
\n
>>> nums=[1,2,5,10,3,100,9,24]\r\n>>> newnums=list(filter(lambda x:x>=5, nums))\r\n>>> newnums<\/pre>\n
\nQ.15. What is the best code you can write to swap two numbers?<\/strong>
\nAns.<\/strong> I can perform the swapping in one statement.<\/span><\/p>\n>>> a,b=b,a<\/pre>\n
>>> a,b=2,3\r\n>>> a,b=b,a\r\n>>> a,b<\/pre>\n
\nQ.16. Explain the problem with the following piece of code-<\/strong>
\n>>> def func(n=[]):<\/b>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0#playing around<\/b>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 pass<\/b>
\n>>> func([1,2,3])<\/b>
\n>>> func()<\/b>
\n>>> n<\/b>
\nAns.<\/strong> The request for <\/span>n<\/span><\/i> raises a NameError. This is since n is a variable local to func and we cannot access it elsewhere. It is also true that Python only evaluates default parameter values once; every invocation shares the default value. If one invocation modifies it, that is what another gets. This means you should only ever use primitives, strings, and tuples as default parameters, not mutable objects.<\/span>
\nBest Python Interview Preparation<\/a><\/strong>
\nQ.17. Can you remove the whitespaces from the string \u201caaa bbb ccc ddd eee\u201d?<\/strong>
\nAns.<\/strong> I can think of two ways to do this.<\/span><\/p>\n\n
>>> s='aaa bbb ccc ddd eee'\r\n>>> s1=''.join(s.split())\r\n>>> s1<\/pre>\n
\n
>>> s='aaa bbb ccc ddd eee'\r\n>>> s1=str(''.join(([i for i in s if i!=' '])))\r\n>>> s1<\/pre>\n
\nQ.18. Given the first and last names of all employees in your firm, what data type will you use to store it?<\/strong>
\nAns.<\/strong> I can use a dictionary to store that. It would be something like this-<\/span>
\n{\u2018first_name\u2019:\u2019Ayushi\u2019,\u2019second_name\u2019:\u2019Sharma\u2019}<\/strong>
\nQ.19. What do you see below?<\/strong>
\ns = a + \u2018[\u2018 + b + \u2018:\u2019 + c + \u2018]\u2019<\/b>
\nAns.<\/strong> This is string concatenation. If a, b, and c are strings themselves, then it works fine and concatenates the strings around the strings \u2018[\u2018, \u2018:\u2019, and \u2018]\u2019 as mentioned. If even one of these isn\u2019t a string, this raises a TypeError.<\/span>
\nQ.20. If a function does not have a return statement, is it valid?<\/strong>
\nAns.<\/strong> Very conveniently. A function that doesn\u2019t return anything returns a None object. Not necessarily does the return keyword mark the end of a function; it merely ends it when present in the function. Normally, a block of code marks a function and where it ends, the function body ends.<\/span>
\nQuestions for Python Interview for freshers – Q. 11,12,13,15,18,20<\/strong>
\nQuestions for Python Interview for experienced – Q. 14,16,17,19<\/strong>
\nQ.21. What good is recursion?<\/strong>
\nAns.<\/strong> With recursion<\/a><\/strong>, we observe the following:<\/span><\/p>\n\n