It's amazing that some specific tasks can always be done easily with Python. Some cumbersome tasks can be done in a single line of code using python. Here are 50 Python single line code examples I collected.

 

1. Letter shifting words: guess whether the number and frequency of letters are the same

from collections import Counter  
 
s1 = 'below'  
s2 = 'elbow'  

print('anagram') if Counter(s1) == Counter(s2) else print('not an anagram')

or we can also do this using the sorted() method like this.

print('anagram') if sorted(s1) == sorted(s2) else print('not an anagram')

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2. Binary to decimal

decimal = int('1010', 2)  
print(decimal) #10

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3. Convert to lowercase

"Hi my name is Allwin".lower() 
# 'hi my name is allwin'  

"Hi my name is Allwin".casefold()  
# 'hi my name is allwin'

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4. Convert to capital letters

"hi my name is Allwin".upper()  
# 'HI MY NAME IS ALLWIN'

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5. Convert string to byte type

"convert string to bytes using encode method".encode()  
# b'convert string to bytes using encode method'

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6. Copy files

import shutil; shutil.copyfile('source.txt', 'dest.txt')

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7. Quick sort

qsort = lambda l : l if len(l)<=1 else qsort([x for x in l[1:] if x < l[0]]) + [l[0]] + qsort([x for x in l[1:] if x >= l[0]])

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8. Sum of N consecutive numbers

sum(range(0, n+1))

This is not efficient and we can do the same using the below formula.

sum_n = n*(n+1)//2

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9. Assignment exchange

a,b = b,a

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10. Fibonacci series

lambda x: x if x<=1 else fib(x-1) + fib(x-2)]

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11. Merge nested lists into one list

[item for sublist in main_list for item in sublist]

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12. Run an HTTP service

python3 -m http.server 8000

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13. Reverse list

numbers[::-1]

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14. Find the factor of a number

import math; fact_5 = math.factorial(5)

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15. List parsing using "for" and "if"

even_list = [number for number in [1, 2, 3, 4] if number % 2 == 0]  
# [2, 4]

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16. Get the longest string from the list

words = ['This', 'is', 'a', 'list', 'of', 'words']
max(words, key=len)
# 'words'

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17. List derivation

li = [num for num in range(0,100)]  
# this will create a list of numbers from 0 to 99

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18. Set derivation

num_set = { num for num in range(0,100)}  
# this will create a set of numbers from 0 to 99

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19. Dictionary derivation

dict_numbers = {x:x*x for x in range(1,5) }  
# {1: 1, 2: 4, 3: 9, 4: 16}

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20. if-else

print("even") if 4%2==0 else print("odd")

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21. Infinite cycle

while 1:0

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22. Check data type

isinstance(2, int)  
isinstance("allwin", str)  
isinstance([3,4,1997], list)

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23. While cycle

a=5  
while a > 0: a = a - 1; print(a)

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24. Use "print()" to write to the file

print("Hello, World!", file=open('file.txt', 'w'))

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25. Calculate the frequency of a character in the string

print("umbrella".count('l'))# 2

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26. Merge two lists

list1.extend(list2)# contents of list 2 will be added to the list1

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27. Merge two dictionaries

dict1.update(dict2)  
# contents of dictionary 2 will be added to the dictionary 1

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28. Merge two sets

set1.update(set2)  
# contents of set2 will be copied to the set1

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29. Timestamp

import time; print(time.time())

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30. Elements with the most occurrences

numbers = [9, 4, 5, 4, 4, 5, 9, 5, 4]  
most_frequent_element = max(set(test_list), key=test_list.count)  
# 4

However, this is not efficient and we can do the same using the collections module in a more efficient way like this.

numbers = [9, 4, 5, 4, 4, 5, 9, 5, 4]  
  
from collections import Counter  
print(Counter(numbers).most_common()[0][0])# 4

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31. Nested list derivation

numbers = [[num] for num in range(10)]  
# [[0], [1], [2], [3], [4], [5], [6], [7], [8], [9]]

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32. Octal to decimal

print(int('30', 8))   
# 24

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33. Convert key value pairs to dictionaries

dict(name='allwin', age=23)

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34. Calculation of quotient and remainder

quotient, remainder = divmod(4,5)

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35. Remove duplicate elements from the list

list(set([4, 4, 5, 5, 6]))

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36. Sort the list in ascending order

First, let us sort the list using the sorted() method. The sorted method will **return the sorted list**.

sorted([5, 2, 9, 1])# [1, 2, 5, 9]

Next, let us sort this using the sort() method. The sort() method will sort the original list and not return anything.

li = [5, 2, 9, 1]  
li.sort()  
  
print(li)  
# 1, 2, 5, 9

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37. Sort the list in descending order

sorted([5, 2, 9, 1], reverse=True)# [9, 5, 2, 1]

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38. Get a string of lowercase letters

import string; print(string.ascii_lowercase)  
# abcdefghijklmnopqrstuvwxyz

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39. Get a string of uppercase letters

import string; print(string.ascii_uppercase)  
# ABCDEFGHIJKLMNOPQRSTUVWXYZ

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40. Get the number from 0 to 9 of string type

import string; print(string.digits)  
# 0123456789

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41. Hexadecimal to decimal

print(int('da9', 16))  
# 3497

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42. Human readable date and time

import time; print(time.ctime())  
# Thu Aug 13 20:16:23 2020

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43. Convert the string type of the list element to integer

list(map(int, ['1', '2', '3']))  
# [1, 2, 3]

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44. Press "key" to sort the dictionary

# d = {'five': 5, 'one': 1, 'four': 4, 'eight': 8}  
{key:d[key] for key in sorted(d.keys())}  
# {'eight': 8, 'five': 5, 'four': 4, 'one': 1}

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45. Sort dictionaries by value

# x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}  
{k: v for k, v in sorted(x.items(), key=lambda item: item[1])}  
# {0: 0, 2: 1, 1: 2, 4: 3, 3: 4}

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46. Rotation list

# li = [1,2,3,4,5]# right to left  
li[n:] + li[:n] # n is the no of rotations  
li[2:] + li[:2]  
[3, 4, 5, 1, 2]# left to right  
li[-n:] + li[:-n]  
li[-1:] + li[:-1]   
[5, 1, 2, 3, 4]

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47. Remove numbers from string

''.join(list(filter(lambda x: x.isalpha(), 'abc123def4fg56vcg2')))  
# abcdeffgvcg

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48. Transpose matrix

list(list(x) for x in zip(*old_list))  
# old_list = [[1, 2, 3], [3, 4, 6], [5, 6, 7]]  
# [[1, 3, 5], [2, 4, 6], [3, 6, 7]]

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49. Filter even numbers from the list

list(filter(lambda x: x%2 == 0, [1, 2, 3, 4, 5, 6] ))  
# [2, 4, 6]

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50. Unpacking

a, *b, c = [1, 2, 3, 4, 5]  
print(a) # 1  
print(b) # [2, 3, 4]  
print(c) # 5

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come from: https://blog.csdn.net/os373/article/details/121035063? spm=1000.2115.3001.5927#8_ n__ forty-eight