如何使用带有数据帧的python创建函数以在动态列名称上删除NaN值？

如何解决如何使用带有数据帧的python创建函数以在动态列名称上删除NaN值？

我想创建删除NaN值的函数，但我需要此函数是动态的，这意味着最终用户可以选择所需的列名而不是预先选择的列。

标题名称：

['event_type','date','event_city','event_mouhafaza','number_person','groups']

这是功能：

def drop_nan(self,df):
        df.dropna(subset = ["number_person"],inplace=True)

我需要允许用户将 number_person 标头的名称更改为上述列表项之一。

下面的代码显示了如何显示带有复选框的标题列表，以便允许用户检查他想要的内容。

系统崩溃并显示以下错误：

self.drop_nan_value.clicked.connect(lambda: self.drop_nan(self.df,self.colname)) AttributeError: 'Widget' object

没有属性“ colname”

代码：

import pandas as pd

from PandasModel import PandasModel

import seaborn as sns
import cufflinks as cf
import plotly
import plotly.offline as py
import plotly.express as px 
import plotly.graph_objs as go
from plotly.offline.offline import iplot
cf.go_offline()
cf.set_config_file(offline=False,world_readable=True)


class Widget(QtWidgets.QWidget):
    def __init__(self,parent=None):
        QtWidgets.QWidget.__init__(self,parent=None)
        self.gridLayout_3 = QtWidgets.QGridLayout(self)
        self.gridLayout_3.setObjectName("gridLayout_3")
       
        self.gridLayout_2 = QtWidgets.QGridLayout()
        self.gridLayout_2.setObjectName("gridLayout_2")
       
        self.gridLayout = QtWidgets.QGridLayout()
        self.gridLayout.setObjectName("gridLayout")
        
        self.pathLE = QtWidgets.QLineEdit(self)
        self.gridLayout_2.addWidget(self.pathLE,1,1)
        

        
        self.loadBtn = QtWidgets.QPushButton("Select File",self)
        self.loadBtn.clicked.connect(self.loadFile)
        self.gridLayout_2.addWidget(self.loadBtn,1)
        self.gridLayout_3.addLayout(self.gridLayout_2,4)

       
        self.displayHeader = QtWidgets.QPushButton("Display header",self)
        self.displayHeader.clicked.connect(lambda: self.print_df_header(self.df))
        self.gridLayout.addWidget(self.displayHeader,2,1)
        
        self.displayDF_checked_header = QtWidgets.QPushButton("Print checked item",self)
        self.displayDF_checked_header.clicked.connect(lambda: self.setItems(self.df))
        self.gridLayout.addWidget(self.displayDF_checked_header,5,1)

        self.drop_nan_value = QtWidgets.QPushButton("drop  NaN Values",self)
        self.drop_nan_value.clicked.connect(lambda: self.drop_nan(self.df,self.colname))
        self.gridLayout.addWidget(self.drop_nan_value,4,1)
        self.gridLayout_2.addLayout(self.gridLayout,1)   

        
        self.header_list = QtWidgets.QListWidget(self)
        self.header_list.setObjectName("listWidget")
        self.header_list.itemSelectionChanged.connect(self.selectionChanged)
        self.gridLayout_3.addWidget(self.header_list,1)
   

        self.pandasTv = QtWidgets.QTableView(self)
        self.verticalLayout.addWidget(self.pandasTv)

        self.pandasTv.setSortingEnabled(True)


     def loadFile(self):
        fileName,_ = QtWidgets.QFileDialog.getOpenFileName(self,"Open File","","CSV Files (*.csv)");
        self.pathLE.setText(fileName)
        df = pd.read_csv(fileName)
        model = PandasModel(df)
        self.pandasTv.setModel(model)
        self.df = df

     def print_df_header(self,df):
        savelist = list(self.df)
        for item in savelist:
            qitem = QtWidgets.QListWidgetItem ( ) 
            qitem.setText ( item ) 
            qitem.setCheckState ( QtCore.Qt.Unchecked ) 
            self.header_list.addItem ( qitem )
        print(savelist)

     def selectionChanged(self):
     checked = []
     for row in range(self.header_list.count()):
        item = self.header_list.item(row)
        if item.checkState():
            checked.append(item)
     print("Checked items: ",",".join(i.text() for i in checked))

     def drop_nan(self,df,colname):
        df.dropna(subset = [colname],inplace=True)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())  

解决方法

您可以从用户那里获取他/她想从中删除NAs的熊猫列名称。如在代码中所示，我可以看到它位于self.drop_nan_value中……因此只需按如下所示修改您的drop_nan函数-

def drop_nan(self):
    self.df = self.df.dropna(subset=[self.drop_nan_value])

如果用户想从多个列中删除NAs，则将所有这些列名称添加到python列表中，说drop_col_list和drop_nan函数可以修改为-

def drop_nan(self):
    self.df = self.df.dropna(subset=drop_col_list)