[英]How to create a new column in pandas dataframe based on a condition?
[英]How Create new column in Pandas based on condition
快速愚蠢的問題-我確定之前有人問過這個問題,但無法提交詳細信息。 我有一個數據框 df_students 如下 -
Student ID, Subjects , MArks_Received, Marks
222 English 3 90
222 Maths 3 80
222 Science 3 70
223 English 2 90
223 Maths 2 80
224 Maths 2 80
我正在尋找基於主題和接收條件的以下輸出,如果每個學生的行數不匹配,則必須添加額外的 Colum (PENDING) 或 Received。
Student ID, Subjects , Expected_Rows, Marks, State
222 English 3 90 Received
222 Maths 3 80 Received
222 Science 3 70 Received
223 English 2 90 Received
223 Maths 2 80 Received
224 Maths 2 80 PENDING
由於我有 "224" 的 Expected_Rows 2 ,但只收到了 1 ,我應該將其標記為“Pending”。
我能夠匯總如下總分,但無法弄清楚如何添加狀態。 任何幫助都值得贊賞。
df_aggregate = df_students.groupby(['Student ', 'Marks'])['Marks'].agg(sum).reset_index()
有很多方法,請參閱下面是否有幫助:
添加一個新列'count'
,然后'State'
基於:
df['Count'] = df.groupby('Student ID')['Student ID'].transform('count')
df['State'] = np.where(df['Count'] != df['MArks_Received'], 'PENDING','Received')
如果您不想添加新列,請使用以下內容:
df['State'] = np.where(df.groupby('Student ID')['Student ID'].transform('count') != df['MArks_Received'], 'PENDING','Received')
它考慮'Student ID'
的計數與'Expected Rows'
不匹配'Expected Rows'
。
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