使用CSV文件從考勤日志報告中過濾時間

Question

我在csv文件中有一個員工的出勤日志報告，我需要過濾所有遲到的員工出勤（9:30之后）。

我創建了一個產生出勤率的函數。 員工輸入其ID並標記出勤。 該程序從計算機時鍾獲取日期和時間，並將出勤記錄存儲在日志文件中。

#function that generated an attendance 
def attandance_log():

    dnt =  datetime.datetime.now()
    dnt_string = dnt.strftime("%d/%m/%Y %H:%M:%S")
    empid = input("Enter Your ID :")
    empname=input("Enter Your Name :")
    df1 = pd.DataFrame(data=[[dnt_string,empid,empname]],columns=["Today's Date & Time", "Employee's ID", "Employee's Name"])
    with open('/Users/sapir/Documents/python/final project- employee attandance log/attandance_log.csv', 'a') as f:
        df1.to_csv(f, header=False)
    return df1
attandance_df= attandance_log()

#the functions that filters all late attendances:
def late_emp_report():

    df = pd.read_csv('/Users/sapir/Documents/python/final project- employee attandance log/attandance_log.csv',index_col=0)
    #df[1] = pd.to_datetime(df[1], unit='s')
    # Add to employees list existing file
    #df.loc['29/07/2019 09:30:00': ].head()------->???
    #df_filtered = df[(df[1] <= datetime.time(9,30))]------>???

    print (df_filtered)
    with open('/Users/sapir/Documents/python/final project- employee attandance log/emplist.csv', 'w') as f:
        df.to_csv(f, header=False)
    return df


late_emp_report()

我不知道如何創建一個文件來顯示9:30之后的所有出勤情況...

Answer 1

您可以將這種形式的過濾器立即應用於整個數據幀：

filtered_df = original_df[original_df[column_to_filter_on] > somevalue]

這將返回一個數據幀，其中包含original_df中的所有行，其中列值column_to_filter_on大於some_value

我更喜歡不使用1作為列標題，而是給它起一個名字-以防止以后與索引混淆。

嘗試比較循環時間（9:30）與日期時間時會遇到問題，因此，您可以使用.apply()引入late_flag來比較該日期與9:30的任何日期時間。

# 'Initialize' datetime column in order to later grab df[1]
df['datetime'] = 0
df['datetime'] = pd.to_datetime(df[1], unit='s')

# Calculate late flag - compare datetime vs 9:30 on the same date for each row
df['late_flag'] = df['datetime'].apply(lambda x: 1 if x > x.replace(hour=9, minute=30, second=0, microsecond=0) else 0)

# Filter out just where late_flag is 1
df_filtered = df[df['late_flag'] == 1]