超实用的30个 Python 案例

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

from math import ceil    def chunk(lst, size):        return list(            map(lambda x: lst[x * size:x * size + size],                list(range(0, ceil(len(lst) / size)))))    chunk([1,2,3,4,5],2) # [[1,2],[3,4],5]

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 retdef deep_flatten(lst):    result = []    result.extend(        spread(list(map(lambda x: deep_flatten(x) if type(x) == list else x, lst))))    return resultdeep_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 floordifference_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 + bdef subtract(a, b):    return a - ba, b = 4, 5print((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) # Truehas_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 ca = {  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 timestart_time = time.time()a = 1b = 2c = a + bprint(c) #3end_time = time.time()total_time = end_time - start_timeprint("Time: ", total_time)# ( Time:  , 1.1205673217773438e-05)

try:    2*3except 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 operatoraction = {    "+": operator.add,    "-": operator.sub,    "/": operator.truediv,    "*": operator.mul,    "**": pow}print(action[ - ](50, 25)) # 25

from copy import deepcopyfrom random import randintdef 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 retspread([1,2,3,[4,5,6],[7],8,9]) # [1,2,3,4,5,6,7,8,9]

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

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