用Python元素树解析XML

我有一个很长的XML文档，其结构如下：

<carrierData>
    <inspections>
        <inspection inspection_date="2013-01-16" report_state="TX" report_number="TX130G0ELJ05" level="1" time_weight="1">
           <drivers>
              <driver driver_type="Primary Driver" first_name="JOHN" last_name="SMITH" date_of_birth="1962-11-20" license_state="TX" License_number="12345678"/>
              <driver driver_type="CoDriver"/>
           </drivers>
           <vehicles>
               <vehicle unit="1" vehicle_id_number="2HSCAAXN02C039269" unit_type="Truck Tractor" license_state="TX" license_number="1B13577"/>
               <vehicle unit="2" vehicle_id_number="1GRAA76228S702393" unit_type="Semi-Trailer" license_state="TX" license_number="X99757"/>
           </vehicles>
           <violations>
               <violation code="393.11" description="No/defective lighting devices/reflective devices/projected" oos="N" time_severity_weight="3" BASIC="Vehicle Maint."/>
               <violation code="393.53(b)" description="Automatic brake adjuster CMV manufactured on or after 10/20/1994 - air brake" oos="N" time_severity_weight="4" BASIC="Vehicle Maint."/>
               <violation code="393.47(e)" description="Clamp/Roto-Chamber type brake(s) out of adjustment" oos="N" time_severity_weight="4" BASIC="Vehicle Maint."/>
               <violation code="396.3(a)(1)" description="Inspection/repair and maintenance parts and accessories" oos="N" time_severity_weight="2" BASIC="Vehicle Maint."/>
           </violations>
    </inspection>

for x in codes:
    for node in tree.iter('inspection'):
        if node.attrib['report_number'] == x:
            primary_driver = [d for d in node.iter('driver') if d.attrib['driver_type'] == "Primary Driver"]
            primary_driver = primary_driver[0]
            first_name = primary_driver.attrib['first_name']
            last_name = primary_driver.attrib['last_name']
            print first_name, last_name

---

我是一名编程新手，因此我可能遗漏了一些显而易见的内容，但如果没有引用错误，我很难追踪问题。

您对这一行有何打算

if ['report_id'] == [x]:

使用此代码，您正在测试

['report\u id']==['TX3YZ8HQE1X1']

，

['report\u id']==['TX3YAEHQE15W']

，等等，这永远不会是真的。因此，这就是为什么您的代码在退出时没有打印任何内容或给出错误

您发布的XML中没有任何名为

report\u id

的内容，您是指

report\u number

如果要获取

代码

列表中所有

报告编号

的主要驱动程序的名字，请尝试以下操作：

<carrierData>
    <inspections>
        <inspection inspection_date="2013-01-16" report_state="TX" report_number="TX130G0ELJ05" level="1" time_weight="1">
           <drivers>
              <driver driver_type="Primary Driver" first_name="JOHN" last_name="SMITH" date_of_birth="1962-11-20" license_state="TX" License_number="12345678"/>
              <driver driver_type="CoDriver"/>
           </drivers>
           <vehicles>
               <vehicle unit="1" vehicle_id_number="2HSCAAXN02C039269" unit_type="Truck Tractor" license_state="TX" license_number="1B13577"/>
               <vehicle unit="2" vehicle_id_number="1GRAA76228S702393" unit_type="Semi-Trailer" license_state="TX" license_number="X99757"/>
           </vehicles>
           <violations>
               <violation code="393.11" description="No/defective lighting devices/reflective devices/projected" oos="N" time_severity_weight="3" BASIC="Vehicle Maint."/>
               <violation code="393.53(b)" description="Automatic brake adjuster CMV manufactured on or after 10/20/1994 - air brake" oos="N" time_severity_weight="4" BASIC="Vehicle Maint."/>
               <violation code="393.47(e)" description="Clamp/Roto-Chamber type brake(s) out of adjustment" oos="N" time_severity_weight="4" BASIC="Vehicle Maint."/>
               <violation code="396.3(a)(1)" description="Inspection/repair and maintenance parts and accessories" oos="N" time_severity_weight="2" BASIC="Vehicle Maint."/>
           </violations>
    </inspection>

for x in codes:
    for node in tree.iter('inspection'):
        if node.attrib['report_number'] == x:
            primary_driver = [d for d in node.iter('driver') if d.attrib['driver_type'] == "Primary Driver"]
            primary_driver = primary_driver[0]
            first_name = primary_driver.attrib['first_name']
            last_name = primary_driver.attrib['last_name']
            print first_name, last_name

---

但是，这段代码有一个性能问题。您正在对

code

中的每一个代码循环整个XML文档。这有

O（代码的数量*记录的数量）

，即

O（N**2）

。您可以在

O（N）

步骤中执行此操作，方法是在文档上循环一次，然后使用a来确定是否应包含记录。

谢谢您，先生！成功了！我的代码中确实有正确的“report\u number”属性，但我想当我第一次键入它时，我的代码中有“report\u id”，所以很抱歉这里的混乱。否则，它给了我我所需要的，看到这里的答案给了我一个更精确的理解，我试图做什么。上面还建议使用set（）函数，我确实实现了它，效果非常好。再次感谢！