30秒学会30个超实用Python代码片段【收藏版】

def all_unique(lst):
  return len(lst) == len(set(lst))
x = [1,1,2,2,3,2,3,4,5,6]
y = [1,2,3,4,5]
all_unique(x) # False
 
all_unique(y) # True

from collections import Counter
def anagram(first, second):
 return Counter(first) == Counter(second)
anagram("abcd3", "3acdb") # True 

import sys 
variable = 30 
print(sys.getsizeof(variable)) # 24 

def byte_size(string):
  return(len(string.encode('utf-8')))
byte_size('😀') # 4
byte_size('Hello World') # 11

n = 2; 
s ="Programming"; 
print(s * n); # ProgrammingProgramming

s = "programming is awesome"
print(s.title()) # Programming Is Awesome

def chunk(list, size):
   return [list[i:i+size] for i in range(0,len(list), size)]

def compact(lst):
  return list(filter(bool, lst))
compact([0, 1, False, 2, '', 3, 'a', 's', 34]) # [ 1, 2, 3, 'a', 's', 34 ]

array = [['a', 'b'], ['c', 'd'], ['e', 'f']]
transposed = zip(*array)
 
print(transposed) # [('a', 'c', 'e'), ('b', 'd', 'f')]

a = 3
print( 2 < a < 8) # True
print(1 == a < 2) # False

hobbies = ["basketball", "football", "swimming"]
print("My hobbies are: " + ", ".join(hobbies)) # My hobbies are: basketball, football, swimming

import re
def count_vowels(str):
  return len(len(re.findall(r'[aeiou]', str, re.IGNORECASE))
count_vowels('foobar') # 3
count_vowels('gym') # 0

def decapitalize(string):
   return str[:1].lower() + str[1:]
decapitalize('FooBar') # 'fooBar'
decapitalize('FooBar') # 'fooBar'

def spread(arg):
  ret = []
  for i in arg:
    if isinstance(i, list):
      ret.extend(i)
    else:
      ret.append(i)
  return ret
def deep_flatten(lst):
  result = []
  result.extend(
    spread(list(map(lambda x: deep_flatten(x) if type(x) == list else x, lst))))
  return result
deep_flatten([1, [2], [[3], 4], 5]) # [1,2,3,4,5] 

def difference(a, b):
  set_a = set(a)
  set_b = set(b)
  comparison = set_a.difference(set_b)
  return list(comparison)
difference([1,2,3], [1,2,4]) # [3]

def difference_by(a, b, fn):
  b = set(map(fn, b))
  return [item for item in a if fn(item) not in b]
from math import floor
difference_by([2.1, 1.2], [2.3, 3.4],floor) # [1.2]
difference_by([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], lambda v : v['x']) # [ { x: 2 } ] 

def add(a, b):
  return a + b
def subtract(a, b):
  return a – b
a, b = 4, 5
print((subtract if a > b else add)(a, b)) # 9  

def has_duplicates(lst):
  return len(lst) != len(set(lst))
x = [1,2,3,4,5,5]
y = [1,2,3,4,5]
has_duplicates(x) # True
has_duplicates(y) # False 

def merge_two_dicts(a, b):
  c = a.copy()  # make a copy of a 
  c.update(b)  # modify keys and values of a with the ones from b
  return c
a = { 'x': 1, 'y': 2}
b = { 'y': 3, 'z': 4}
print(merge_two_dicts(a, b)) # {'y': 3, 'x': 1, 'z': 4}

def merge_dictionaries(a, b)
  return {**a, **b}
a = { 'x': 1, 'y': 2}
b = { 'y': 3, 'z': 4}
print(merge_dictionaries(a, b)) # {'y': 3, 'x': 1, 'z': 4}

def to_dictionary(keys, values):
  return dict(zip(keys, values))
keys = ["a", "b", "c"]  
values = [2, 3, 4]
print(to_dictionary(keys, values)) # {'a': 2, 'c': 4, 'b': 3}

list = ["a", "b", "c", "d"]
for index, element in enumerate(list): 
  print("Value", element, "Index ", index, )
# ('Value', 'a', 'Index ', 0)
# ('Value', 'b', 'Index ', 1)
#('Value', 'c', 'Index ', 2)
# ('Value', 'd', 'Index ', 3)  

import time
start_time = time.time()
a = 1
b = 2
c = a + b
print(c) #3
end_time = time.time()
total_time = end_time - start_time
print("Time: ", total_time)
# ('Time: ', 1.1205673217773438e-05)

try:
  2*3
except TypeError:
  print("An exception was raised")
else:
  print("Thank God, no exceptions were raised.")
#Thank God, no exceptions were raised.

def most_frequent(list):
  return max(set(list), key = list.count)
list = [1,2,1,2,3,2,1,4,2]
most_frequent(list) 

def palindrome(string):
  from re import sub
  s = sub('[\W_]', '', string.lower())
  return s == s[::-1]
palindrome('taco cat') # True

import operator
action = {
  "+": operator.add,
  "-": operator.sub,
  "/": operator.truediv,
  "*": operator.mul,
  "**": pow
}
print(action['-'](50, 25)) # 25

from copy import deepcopy
 from random import randint
def shuffle(lst):
  temp_lst = deepcopy(lst)
  m = len(temp_lst)
  while (m):
    m -= 1
    i = randint(0, m)
    temp_lst[m], temp_lst[i] = temp_lst[i], temp_lst[m]
  return temp_lst
foo = [1,2,3]
shuffle(foo) # [2,3,1] , foo = [1,2,3]

def spread(arg):
   ret = []
  for i in arg:
    if isinstance(i, list):
      ret.extend(i)
    else:
      ret.append(i)
  return ret
spread([1,2,3,[4,5,6],[7],8,9]) # [1,2,3,4,5,6,7,8,9]

def swap(a, b):
 return b, a
a, b = -1, 14
swap(a, b) # (14, -1)

d = {'a': 1, 'b': 2}
print(d.get('c', 3)) # 3