10 Questions, 10 Minutes – SQL/R/Python – 3/100

1.What will the following code output?

>>> word=’abcdefghij’ 
>>> word[:3]+word[3:]

The output is ‘abcdefghij’. The first slice gives us ‘abc’, the next gives us ‘defghij’.

2.How will you convert a list into a string?

We will use the join() method for this.


>>> nums=['one','two','three','four','five','six','seven']
>>> s=' '.join(nums)
>>> s

‘one two three four five six seven’

3. How will you remove a duplicate element from a list?

We can turn it into a set to do that.

>>> list=[1,2,1,3,4,2] 
>>> set(list) 
{1, 2, 3, 4} 

4. Explain the //, %, and ** operators in Python.

The // operator performs floor division. It will return the integer part of the result on division.

>>> 7//2 
3

Normal division would return 3.5 here.

Similarly, ** performs exponentiation. a**b returns the value of a raised to the power b.

>>> 2**10 
1024

Finally, % is for modulus. This gives us the value left after the highest achievable division.

>>> 13%7 
6

5. Explain identity operators in Python.

The operators ‘is’ and ‘is not’ tell us if two values have the same identity. 1.

>>> 10 is '10' 
False
 >>> True is not False 
True 

6. What are numbers?

Python provides us with five kinds of data types:

Numbers – Numbers use to hold numerical values.

>>> a=7.0 

7. What are Strings?

A string is a sequence of characters. We declare it using single or double quotes.

>>> title="Ayushi's Book" 


8. What are Lists?

Lists – A list is an ordered collection of values, and we declare it using square brackets.

>>> colors=['red','green','blue'] 
>>> type(colors)

<class ‘list’>



9. What are Tuples?

Tuples – A tuple, like a list, is an ordered collection of values. The difference. However, is that a tuple is immutable. This means that we cannot change a value in it.

>>> name=(‘Ayushi’,’Sharma’) 


>>> name[0]=’Avery’ 


Traceback (most recent call last):

File “<pyshell#129>”, line 1, in <module>

name[0]=’Avery’

TypeError: ‘tuple’ object does not support item assignment


10. What are Disctionary?

Dictionary – A dictionary is a data structure that holds key-value pairs. We declare it using curly braces.

>>> squares={1:1,2:4,3:9,4:16,5:25} 
>>> type(squares)

<class ‘dict’>
1. >>> type({})

<class ‘dict’>
We can also use a dictionary comprehension:

>>> squares={x:x**2 for x in range(1,6)} 
>>> squares {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}


Author: TheDataMonk

I am the Co-Founder of The Data Monk. I have a total of 6+ years of analytics experience 3+ years at Mu Sigma 2 years at OYO 1 year and counting at The Data Monk I am an active trader and a logically sarcastic idiot :)