HackerRank Python Solution - Errors and Exception - Incorrect Regex

• You are given a string S.

• Your task is to find out whether S is a valid regex or not.

Input Format:

• The first line contains integer T, the number of test cases.

• The next T lines contain the string S.

HackerRank Python Solution - Errors and Exception

Errors detected during execution are called exceptions.

Examples:

ZeroDivisionError:

This error is raised when the second argument of a division or modulo operation is zero.

 

>>> a = '1'
>>> b = '0'
>>> print int(a) / int(b)
>>> ZeroDivisionError: integer division or modulo by zero

HackerRank Python Solution - Date and Time - Time Delta

• When users post an update on social media, such as a URL, image, status update, etc., other users in their network are able to view this new post on their news feed. Users can also see exactly when the post was published, i.e, how many hours, minutes, or seconds ago.

• Since sometimes posts are published and viewed in different time zones, this can be confusing. You are given two timestamps of one such post that a user can see on his newsfeed in the following format:

• Day dd Mon yyyy hh:mm:ss +xxxx

• Here +xxxx represents the time zone. Your task is to print the absolute difference (in seconds) between them.

HackerRank Python Solution - Date and Time - Calendar Module

• The calendar module allows you to output calendars and provides additional useful functions for them.

• class calendar.TextCalendar([firstweekday])

• This class can be used to generate plain text calendars.

Sample Code:

HackerRank Python Solution - Collections Topic - Counter()

A counter is a container that stores elements as dictionary keys and their counts are stored as dictionary values.

Sample Code:

>>> from collections import Counter
>>> 
>>> myList = [1,1,2,3,4,5,3,2,3,4,2,1,2,3]
>>> print Counter(myList)
Counter({2: 4, 3: 4, 1: 3, 4: 2, 5: 1})
>>>
>>> print Counter(myList).items()
[(1, 3), (2, 4), (3, 4), (4, 2), (5, 1)]
>>> 
>>> print Counter(myList).keys()
[1, 2, 3, 4, 5]
>>> 
>>> print Counter(myList).values()
[3, 4, 4, 2, 1]