更高效地將xml文件轉換爲數據框

Question

我試圖將大文件（53MB）XML文件加載到熊貓數據框中。這裏有3行實際數據（從NTSB航空事故報告公共數據庫），但實際的文件有77257行：

<?xml version="1.0"?> 
<DATA xmlns="http://www.ntsb.gov"> 
<ROWS> 
    <ROW EventId="20150901X74304" InvestigationType="Accident" AccidentNumber="GAA15CA244" EventDate="09/01/2015" Location="Truckee, CA" Country="United States" Latitude="" Longitude="" AirportCode="" AirportName="" InjurySeverity="" AircraftDamage="" AircraftCategory="" RegistrationNumber="N786AB" Make="JOE SALOMONE" Model="SUPER CUB SQ2" AmateurBuilt="" NumberOfEngines="" EngineType="" FARDescription="" Schedule="" PurposeOfFlight="" AirCarrier="" TotalFatalInjuries="" TotalSeriousInjuries="" TotalMinorInjuries="" TotalUninjured="" WeatherCondition="" BroadPhaseOfFlight="" ReportStatus="Preliminary" PublicationDate=""/> 
    <ROW EventId="20150901X92332" InvestigationType="Accident" AccidentNumber="CEN15LA392" EventDate="08/31/2015" Location="Houston, TX" Country="United States" Latitude="29.809444" Longitude="-95.668889" AirportCode="IWS" AirportName="WEST HOUSTON" InjurySeverity="Non-Fatal" AircraftDamage="Substantial" AircraftCategory="Airplane" RegistrationNumber="N452CS" Make="CESSNA" Model="T240" AmateurBuilt="No" NumberOfEngines="" EngineType="" FARDescription="Part 91: General Aviation" Schedule="" PurposeOfFlight="Instructional" AirCarrier="" TotalFatalInjuries="" TotalSeriousInjuries="" TotalMinorInjuries="" TotalUninjured="2" WeatherCondition="VMC" BroadPhaseOfFlight="LANDING" ReportStatus="Preliminary" PublicationDate="09/04/2015"/> 
    <ROW EventId="20150729X33718" InvestigationType="Accident" AccidentNumber="CEN15FA325" EventDate="" Location="Truth or Consequences, NM" Country="United States" Latitude="33.250556" Longitude="-107.293611" AirportCode="TCS" AirportName="TRUTH OR CONSEQUENCES MUNI" InjurySeverity="Fatal(2)" AircraftDamage="Substantial" AircraftCategory="Airplane" RegistrationNumber="N32401" Make="PIPER" Model="PA-28-151" AmateurBuilt="No" NumberOfEngines="1" EngineType="Reciprocating" FARDescription="Part 91: General Aviation" Schedule="" PurposeOfFlight="Personal" AirCarrier="" TotalFatalInjuries="2" TotalSeriousInjuries="" TotalMinorInjuries="" TotalUninjured="" WeatherCondition="" BroadPhaseOfFlight="UNKNOWN" ReportStatus="Preliminary" PublicationDate="08/10/2015"/> 
</ROWS> 
</DATA> 

下面的代碼，這是我改編自here，工作，但它是非常緩慢對於這些數據（我的系統超過30分鐘）。我似乎無法得到原始示例發佈的解決方案，因爲我的XML結構不同。有沒有更有效的方法來加載這些數據？

path_to_xml_file = mypath 

import pandas as pd 
import xml.etree.ElementTree as ET 

#Load xml file data 
tree = ET.parse(path_to_xml_file) 
root = tree.getroot() 

#Grab list of column names 
aviationdata_column_names = root[0][0].attrib.keys()    
#Create empty dataframe 
aviationdata_df = pd.DataFrame(columns=aviationdata_column_names) 

#Loop through tree and append to dataframe 
for i in range(0,len(root[0])-1): 
    new_row = pd.Series(root[0][i].attrib) 
    new_row.name = i 
    aviationdata_df = aviationdata_df.append(new_row) 

有圍繞互聯網（here，here和here）發佈的類似問題的各種解決方案，但我還沒有運氣實現它們。版本問題可能會對其中一些負責（我正在使用Python 2.7）。

Answer 1

由於您的XML是以屬性爲中心的（沒有元素值），因此請考慮在存儲在字典鍵/值對中的所有屬性中迭代xml.etree.ElementTree。

下面結合屬性的列表詞典集中到DataFrame()電話：

import pandas as pd 
import xml.etree.ElementTree as ET 

path_to_xml_file = mypath 

# Load xml file data 
tree = ET.parse(path_to_xml_file) 

data = [] 
for el in tree.iterfind('./*'): 
    for i in el.iterfind('*'): 
     data.append(dict(i.items())) 

df = pd.DataFrame(data) 

輸出

# FIRST FEW COLUMNS 
print(df[list(range(12))]) 

# AccidentNumber AirCarrier AircraftCategory AircraftDamage AirportCode     AirportName AmateurBuilt BroadPhaseOfFlight  Country  EngineType EventDate   EventId 
# 0  GAA15CA244                              United States     09/01/2015 20150901X74304 
# 1  CEN15LA392     Airplane Substantial   IWS    WEST HOUSTON   No   LANDING United States     08/31/2015 20150901X92332 
# 2  CEN15FA325     Airplane Substantial   TCS TRUTH OR CONSEQUENCES MUNI   No   UNKNOWN United States Reciprocating    20150729X33718