Python technical interview questions and answers are widely asked in software development, data science, automation, and machine learning roles. Python is one of the most popular languages due to its simplicity and power, so companies expect candidates to understand core topics like variables, loops, functions, OOP, modules, file handling, exceptions, and libraries. Companies like TCS, Infosys, Cognizant, Capgemini, and Wipro frequently include Python questions in interviews and online tests. This guide provides clear explanations for the most important Python questions, making it useful for freshers preparing for placement interviews as well as experienced developers. You can also download Python interview PDFs and practice coding exercises to strengthen your preparation.
Python developers can enhance their capabilities by exploring data science applications and machine learning implementations
Showing 10 of 69 questions
1. What is Python?
Python is an interpreted, interactive, object-oriented programming language. It incorporates modules, exceptions, dynamic typing, very high level dynamic data types, and classes. Python combines remarkable power with very clear syntax. It has interfaces to many system calls and libraries, as well as to various window systems, and is extensible in C or C++. It is also usable as an extension language for applications that need a programmable interface. Finally, Python is portable: it runs on many
2. Is there a tool to help find bugs or perform static analysis?
Yes.
PyChecker is a static analysis tool that finds bugs in Python source code and warns about code complexity and style.
Pylint is another tool that checks if a module satisfies a coding standard, and also makes it possible to write plug-ins to add a custom feature.
3. How can I find the methods or attributes of an object?
For an instance x of a user-defined class, dir(x) returns an alphabetized list of the names containing the instance attributes and methods and attributes defined by its class.
4. Is there an equivalent of C's "?:" ternary operator?
No.
5. How do I convert a number to a string?
To convert, e.g., the number 144 to the string '144', use the built-in function str(). If you want a hexadecimal or octal representation, use the built-in functions hex() or oct(). For fancy formatting, use the % operator on strings, e.g. "%04d" % 144 yields '0144' and "%.3f" % (1/3.0) yields '0.333'. See the library reference manual for details.
6. Is there a scanf() or sscanf() equivalent?
Not as such.
For simple input parsing, the easiest approach is usually to split the line into whitespace-delimited words using the split() method of string objects and then convert decimal strings to numeric values using int() or float(). split() supports an optional "sep" parameter which is useful if the line uses something other than whitespace as a separator.
For more complicated input parsing, regular expressions more powerful than C's sscanf() and better suited for the task.
7. What's a negative index?
Python sequences are indexed with positive numbers and negative numbers. For positive numbers 0 is the first index 1 is the second index and so forth. For negative indices -1 is the last index and -2 is the penultimate (next to last) index and so forth. Think of seq[-n] as the same as seq[len(seq)-n].
Using negative indices can be very convenient. For example S[:-1] is all of the string except for its last character, which is useful for removing the trailing newline from a string.
8. What is a method?
A method is a function on some object x that you normally call as x.name(arguments...). Methods are defined as functions inside the class definition:
class C:
def meth (self, arg):
return arg*2 + self.attribute
9. What is self?
Self is merely a conventional name for the first argument of a method. A method defined as meth(self, a, b, c) should be called as x.meth(a, b, c) for some instance x of the class in which the definition occurs; the called method will think it is called as meth(x, a, b, c).
10. Where is the math.py (socket.py, regex.py, etc.) source file?
There are (at least) three kinds of modules in Python:
1. modules written in Python (.py);
2. modules written in C and dynamically loaded (.dll, .pyd, .so, .sl, etc);
3. modules written in C and linked with the interpreter; to get a list of these, type:
import sys
print sys.builtin_module_names