在一個數組中查找匹配的元素

Question

我有一個看起來像這樣的對象列表：

Bidder - Timestamp: 11, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.20 -- missed
Bidder - Timestamp: 13, User ID: 13, Action: BID, Loan ID: 430, Rate: 0.15
Bidder - Timestamp: 17, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.10 -- miss
Bidder - Timestamp: 18, User ID: 1, Action: BID, Loan ID: 431, Rate: 0.15
Bidder - Timestamp: 19, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14
Bidder - Timestamp: 21, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14

我正在嘗試查找所有匹配的User ID但是這樣做很麻煩，我的代碼遇到的問題是我最終錯過了上面顯示的一個匹配ID 。

這是我當前擁有的代碼，該代碼獲取第一個元素並將其與下一個元素進行比較：

self._bidders = [] # List of bidders

for idx, firstElement in enumerate(self._bidders):
    FirstElement = firstElement
    NextElement = self._bidders[(idx + 1) % len(self._bidders)]
    if FirstElement.user_id == NextElement.user_id:
       #Do something

我將如何確保獲得所有匹配的User ID而不丟失任何信息，並且不使用任何導入？，任何建議/幫助將不勝感激。

Answer 1

這是一種將對象列表轉換為數據框的方法，然后您可以從中輕松找到匹配項：

# Create a list of lists
data = ['Bidder - Timestamp: 11, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.20',
        'Bidder - Timestamp: 13, User ID: 13, Action: BID, Loan ID: 430, Rate: 0.15',
        'Bidder - Timestamp: 17, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.10',
        'Bidder - Timestamp: 18, User ID: 1, Action: BID, Loan ID: 431, Rate: 0.15',
        'Bidder - Timestamp: 19, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14',
        'Bidder - Timestamp: 21, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14']

df = pd.DataFrame([d.split(',') for d in data])
# df = pd.DataFrame([list(d).split(',') for d in data]) # Use this for your list of objects

df2 = pd.DataFrame()
for i in range(len(df.columns)):
    name = df.iloc[:,i].str.split(':', expand=True)[0][0].strip()
    values = df.iloc[:,i].str.split(':', expand=True)[1].str.strip()
    df2[name] = values

print(df2)

  Bidder - Timestamp User ID Action Loan ID  Rate
0                 11       8    BID     430  0.20
1                 13      13    BID     430  0.15
2                 17       8    BID     430  0.10
3                 18       1    BID     431  0.15
4                 19       3    BID     431  0.14
5                 21       3    BID     431  0.14

# Find matches
df2[df2['User ID'] == '8']

  Bidder - Timestamp User ID Action Loan ID  Rate
0                 11       8    BID     430  0.20
2                 17       8    BID     430  0.10

Answer 2

試試這個，for循環：

data = ['Bidder - Timestamp: 11, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.20',
        'Bidder - Timestamp: 13, User ID: 13, Action: BID, Loan ID: 430, Rate: 0.15',
        'Bidder - Timestamp: 17, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.10',
        'Bidder - Timestamp: 18, User ID: 1, Action: BID, Loan ID: 431, Rate: 0.15',
        'Bidder - Timestamp: 19, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14',
        'Bidder - Timestamp: 21, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14']
l = [[i.split(':')[0].strip() for i in data[0].split(',')]]
for i in data:
    l.append([x.split(':')[1].strip() for x in i.split(',')])

或單線列表理解：

data = ['Bidder - Timestamp: 11, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.20',
        'Bidder - Timestamp: 13, User ID: 13, Action: BID, Loan ID: 430, Rate: 0.15',
        'Bidder - Timestamp: 17, User ID: 8, Action: BID, Loan ID: 430, Rate: 0.10',
        'Bidder - Timestamp: 18, User ID: 1, Action: BID, Loan ID: 431, Rate: 0.15',
        'Bidder - Timestamp: 19, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14',
        'Bidder - Timestamp: 21, User ID: 3, Action: BID, Loan ID: 431, Rate: 0.14']
l = [[i.split(':')[0].strip() for i in data[0].split(',')]] + [[x.split(':')[1].strip() for x in i.split(',')] for i in data]

Answer 3

您可以使用字典來首先存儲ID在列表中出現的次數。 然后，您可以根據ID是否重復來過濾原始列表：

bidders = [
    Bidder(11, 8, 'BID', 430, 0.20),
    Bidder(13, 13, 'BID', 430, 0.15),
    Bidder(17, 8, 'BID', 430, 0.10),
    Bidder(18, 1, 'BID', 431, 0.15),
    Bidder(19, 3, 'BID', 431, 0.14),
    Bidder(21, 3, 'BID', 431, 0.14)
]

id_counts = {}
for b in bidders:
    if b.user_id in id_counts:
        id_counts[b.user_id] += 1
    else:
        id_counts[b.user_id] = 1

result = [b for b in bidders if id_counts[b.user_id] > 1]
print(result)

產量

[Timestamp: 11, User Id: 8, Action: BID, Loan ID: 430, Rate: 0.2,
 Timestamp: 17, User Id: 8, Action: BID, Loan ID: 430, Rate: 0.1,
 Timestamp: 19, User Id: 3, Action: BID, Loan ID: 431, Rate: 0.14,
 Timestamp: 21, User Id: 3, Action: BID, Loan ID: 431, Rate: 0.14]