我有包含整數(shù)和'NA'值的熊貓數(shù)據(jù)框列。Followinare 是列的唯一值 print(testData.LotFrontage.unique())   ['80' '81' '74' '78' '43' '75' 'NA' '63' '85' '70' '26' '21' '24']我需要用整數(shù) 0 替換這個(gè)字符串 NA。我嘗試了以下代碼NAReplace = {'NA': 0}trainingData.LotFrontage = [NAReplace[item] for item in trainingData.LotFrontage ]我收到一個(gè)錯(cuò)誤    trainingData.LotFrontage = [NAReplace[item] for item in trainingData.LotFrontage ]KeyError: '65'這個(gè)問(wèn)題的原因是什么？有沒(méi)有其他方法可以做到這一點(diǎn)？