發現大多數的數字出現在列表中

Question

def print_most_numbers_occurrences(numbers_str): 
    number_list = list(numbers_str) 
    for i in number_list: 
     i=max(number_list,key=number_list.count) 
    print(i) 

def test_print_most_numbers_occurrences(): 
    print_most_numbers_occurrences('2 3 40 1 5 4 3 3 9 9') 
    print_most_numbers_occurrences('9 30 3 9 3 1 4') 
    print_most_numbers_occurrences('19 30 13 4 9 3 1 4') 


def main(): 
    print(test_print_most_numbers_occurrences()) 


main() 

輸出

None 

它的工作原理，當我嘗試這樣：

>>> lst = [1, 2, 45, 55, 5, 4, 4, 4, 4, 4, 545, 56, 6, 7, 67] 
>>> max(lst,key=lst.count) 
4 

我想，以確定發生的次數最多的號碼。我不確定我的第一個def函數的錯誤。

Answer 1

首先，您需要正確地分析您的輸入。由於其中一個輸入具有雙倍空間，因此您不能僅使用split(" ")。

其次，你不需要循環，因爲max爲你做循環。

def print_most_numbers_occurrences(numbers_str): 
    number_list = [int(x) for x in numbers_str.split()] 
    i=max(number_list,key=number_list.count) 
    print(i) 

既然你是我的循環冒昧地認爲你試圖解決的情況下多個號碼可能具有相同的事件（例如：'2 3 40 1 5 4 3 3 9 9 9'）。在這種情況下，下面的代碼會得到所有的最大值：

def print_most_numbers_occurrences(numbers_str): 
    print(numbers_str.split(" ")) 
    number_list = [int(x) for x in numbers_str.split()] 
    most_occurances = [] 
    for i in set(number_list): 
     occurances = number_list.count(i) 
     if len(most_occurances) == 0: 
      most_occurances.append(i) 
     elif most_occurances[0] < occurances: 
      most_occurances = [i] 
     elif most_occurances[0] == occurances: 
      most_occurances.append(i) 
    print(most_occurances) 

下面是一個使用稍微複雜的代碼更簡潔的版本：

def print_most_numbers_occurrences(numbers_str): 
    number_list = [int(x) for x in numbers_str.split()] 
    result = {i : number_list.count(i) for i in set(number_list)} 
    highest = max(result.values()) 
    most_occurances = [k for k, v in result.items() if v == highest] 
    print(most_occurances) 

如果你需要高效的代碼，這是明智的使用collectionsCounter：

from collections import Counter 

def print_most_numbers_occurrences(numbers_str): 
    number_list = [int(x) for x in numbers_str.split()] 
    result = Counter(number_list) 
    highest = max(result.values()) 
    most_occurances = [k for k, v in result.items() if v == highest] 
    print(most_occurances if len(most_occurances) > 1 else most_occurances[0]) 

Answer 2

使用.split（」「），而不是列表（）

string = '9 30 3 9 3 1 4' 
lst = map(int, filter(None, string.split(' '))) 
print(max(lst, key = lambda x: lst.count(x))) 
# returns 9 

Answer 3

實際上有與代碼一對夫婦的問題，因爲它目前爲。你似乎是打印返回None函數的結果，你沒有正確區分你的字符串：

def print_most_numbers_occurrences(numbers_str): 
    number_list = [int(number) for number in numbers_str.split(' ') if number != ""] 
    for i in number_list: 
     i=max(number_list,key=number_list.count) 
    print(i, number_list.count(i)) 

def test_print_most_numbers_occurrences(): 
    print_most_numbers_occurrences('2 3 40 1 5 4 3 3 9 9') 
    print_most_numbers_occurrences('9 30 3 9 3 1 4') 
    print_most_numbers_occurrences('19 30 13 4 9 3 1 4') 


def main(): 
    test_print_most_numbers_occurrences() 


main() 

Answer 4

您可以輕鬆的寫代碼：

>>> import re 
>>> x 
'2  3 40 1 5 4 3 3 9 9' 
>>> list = re.sub(' +', ' ', x).split(' ') 
>>> list 
['2', '3', '40', '1', '5', '4', '3', '3', '9', '9'] 
>>> max(list, key=list.count) 
'3' 
>>> x = '19 30 13 4 9 3 1 4' 
>>> list = re.sub(' +', ' ', x).split(' ') 
>>> list 
['19', '30', '13', '4', '9', '3', '1', '4'] 
>>> max(list, key=list.count) 
'4' 
>>> 

所以你的功能應該是作爲：

def fun(num_string): 
    num_list = re.sub(' +', ' ', num_string).split(' ') 
    print(max(num_list, key=num_list.count)) # you can write print but I prefer you should use return max(num_list, key=num_list.count) 

Answer 5

使用可以使用str.split()將您的字符串打破列表。然後，您可以使用map將字符串轉換爲整數。 A collections.Counter可用於以相對有效的方式對每個整數的出現進行計數。最後，max帶有一個lambda參數，可以用來提取出目標值的出現次數。

string_list = '2 3 40 1 5 4 3 3 9 9'.split() 
int_list = map(int, string_list) 

from collections import Counter 

counter = Counter(int_list) 
target_value, occurrence_count = max(counter.items(), key=lambda t: t[1]) 

注意，沒有參數提供給str.split並避免使用list.count（這是相當低效在這種情況下）。如果要獲取所有出現次數最多的目標值，可以放棄最後一行並使用：

max_occurrences = max(counter.values()) 
target_values = [k for k, v in counter.items() if v == max_occurrences]