https://gist.github.com/duanbiao2000/5fdb834510694493ed7702a7e557c587

Python Quick Tips

Note:
Goal of this doc is only to make reader aware of few built in methods/modules in Python.

The examples used are just for demonstration purpose and should not be reagrded as complete. Reader is encouraged to check the official documentation of modules to get a complete picture of each module.

Get quotient and remainder with a single operation

## divmod()

dividend = 53
divisor = 10

quotient, remainder = divmod(dividend, divisor)
print('Quotient:', quotient) 
print('Remainder:', remainder)

Quotient: 5
Remainder: 3

Insert to a sorted list

## bisect module

import bisect

sorted_list = [1,3,10]
new_elem = 5
bisect.insort(sorted_list, new_elem)

sorted_list
 

[1, 3, 5, 10]

Check if a given year is leap year or not

## calendar module

import calendar

calendar.isleap(2003)

False

Get unique elements (remove duplicate elements) of a list

big_list = [1,2,1,1,2,5]
unique_list = list(set(big_list))

unique_list

[1, 2, 5]

Reverse a list

a_list = [1,2,3]
rev_list = a_list[::-1]

rev_list
 

[3, 2, 1]

Get elements from odd (or even) indices

pairs = ['John', 'Maria', 'Tom', 'Mary', 'Charles', 'Rose']
wifes = pairs[1::2] # odd indices - start from 1 and take step size of 2
husbands = pairs[0::2] # even indices - start from 0 and step size of 2

print('wifes:', wifes)
print('husbands:', husbands)

wifes: ['Maria', 'Mary', 'Rose']
husbands: ['John', 'Tom', 'Charles']

Convert decimal to binary, octal or hexadecimal and back.

## int(), bin(), oct(), hex()

decimal = 13

binary = bin(decimal) # 0b will be present infront of the actual value 
octal = oct(decimal) # 0o will be present infront of the actual value 
hexa_decimal = hex(decimal) # 0x will be present infront of the actual value


print('Decimal:', decimal)
print('Binary:', binary)
print('Octal:', octal)
print('Hexa decimal', hexa_decimal)

# convert back to decimal - use int() - and pass the base appropriately
int(binary, base=2) == int(octal, base=8) == int(hexa_decimal, base=16) == decimal

Decimal: 13
Binary: 0b1101
Octal: 0o15
Hexa decimal 0xd





True

Get all permutations of a list

## itertools.permutations()

import itertools
a_list = [1,4,2]

for perm in itertools.permutations(a_list):
  print(perm)

(1, 4, 2)
(1, 2, 4)
(4, 1, 2)
(4, 2, 1)
(2, 1, 4)
(2, 4, 1)