numpywhere()方法可用于过滤 Pandas DataFrame。提及where()方法中的条件。首先,让我们使用各自的别名导入所需的库
import pandas as pd import numpy as np
我们现在将创建一个包含产品记录的 Pandas DataFrame
dataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"],"Opening_Stock": [300, 700, 1200, 1500],"Closing_Stock": [200, 500, 1000, 900]})
使用 numpywhere()过滤具有 2 个条件的 DataFrame
resValues1 = np.where((dataFrame['Opening_Stock']>=700) & (dataFrame['Closing_Stock']< 1000)) print"\nFiltered DataFrame Value = \n",dataFrame.loc[resValues1]
让我们where()再次使用 numpy过滤具有 3 个条件的 DataFrame
resValues2 = np.where((dataFrame['Opening_Stock']>=500) & (dataFrame['Closing_Stock']< 1000) & (dataFrame['Product'].str.startswith('C')))
以下是完整代码
import pandas as pd import numpy as np dataFrame = pd.DataFrame({"Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"],"Opening_Stock": [300, 700, 1200, 1500],"Closing_Stock": [200, 500, 1000, 900]}) print"DataFrame...\n",dataFrame # using numpy where() to filter DataFrame with 2 Conditions resValues1 = np.where((dataFrame['Opening_Stock']>=700) & (dataFrame['Closing_Stock']< 1000)) print"\nFiltered DataFrame Value = \n",dataFrame.loc[resValues1] # using numpy where() to filter DataFrame with 3 conditions resValues2 = np.where((dataFrame['Opening_Stock']>=500) & (dataFrame['Closing_Stock']< 1000) & (dataFrame['Product'].str.startswith('C'))) print"\nFiltered DataFrame Value = \n",dataFrame.loc[resValues2]输出结果
这将产生以下输出
DataFrame... Closing_Stock Opening_Stock Product 0 200 300 SmartTV 1 500 700 ChromeCast 2 1000 1200 Speaker 3 900 1500 Earphone Filtered DataFrame Value = Closing_Stock Opening_Stock Product 1 500 700 ChromeCast 3 900 1500 Earphone Filtered DataFrame Value = Closing_Stock Opening_Stock Product 1 500 700 ChromeCast