Python Interviews

• Check whether a number is divisible by another number using the modulus operator, %

n % k == 0

• Open a file:

f=open('text.txt','r')
l=f.readlines()
for i in l:
    print(i.strip('\n'))

• List Comprehension

[x**2 for x in range(1,11) if x % 2 == 1]
[x for x in range(1,11) if x % 2 == 0]

• Slicing Operator:

[start : stop : steps]

• Floor Division operator used for dividing two operands with the result as quotient showing only digits before the decimal point:

10//5 = 2
10.0//5.0 = 2.0
10.0//4 = 2.0
10.0//7 = 1.0

• List vs. Tuple.

List is mutable while the Tuple is not.
A tuple is allowed to be hashed. E.g: using it as a key for dictionaries.

List:  a = [1,3,6]
Tuple: b = (1,4,8)

• Lambda vs. def.

Def can hold multiple expressions while lambda is a uni-expression function.
Def generates a function and designates a name to call it later. Lambda forms a function object and returns it.
Def can have a return statement. Lambda can’t have return statements.
Lambda supports to get used inside a list and dictionary.

• Optional statements possible inside a try-except block:

“else” clause: It is useful if you want to run a piece of code when the try block doesn’t create an exception.
“finally” clause: It is useful when you want to execute some steps which run, irrespective of whether there occurs an exception or not.