如何将嵌套回路更改为递归

Question

有人可以帮助我简化代码吗？我想读取XML中的特定内容，但我不知道文件中有多少层。我所能做的就是继续向嵌套代码添加循环。

pn=[]
tooling=[]
up=[]
step=[]
dept=[]
layer=[]
for item in document.iterfind('CustomerPart'):
    for st in item.find('Route').find('Steps'):
        pn.append(item.findtext('CustPartNumber'))
        tooling.append(item.find('PartParameters').findtext('Value27'))
        up.append(item.findtext('UnitPerPanel'))
        step.append(st.findtext('StepNo'))
        dept.append(st.findtext('ResourceName'))
        layer.append(item.findtext('TopLevelBomPartNumber'))
    for sub in item.find('SubAssemblies'):
        for st2 in sub.find('Route').find('Steps'):
            pn.append(item.findtext('CustPartNumber'))
            tooling.append(item.find('PartParameters').findtext('Value27'))
            up.append(item.findtext('UnitPerPanel'))
            step.append(st2.findtext('StepNo'))
            dept.append(st2.findtext('ResourceName'))
            layer.append(sub.find('PartParameters').findtext('Value113'))
        try:
            for sub1 in sub.find('SubAssemblies'):
                for st3 in sub1.find('Route').find('Steps'):
                    pn.append(item.findtext('CustPartNumber'))
                    tooling.append(item.find('PartParameters').findtext('Value27'))
                    up.append(item.findtext('UnitPerPanel'))
                    step.append(st3.findtext('StepNo'))
                    dept.append(st3.findtext('ResourceName'))
                    layer.append(sub1.find('PartParameters').findtext('Value113'))
        except :
            continue
                   
df = pd.DataFrame({'PartNumber': pn, 'tooling':tooling,'Unit Per Panel':up, 'step':step,'dept':dept,'layer':layer})

Answer 1

为了简化此代码，您实际上不需要递归！您要做的就是删除重复的代码！

添加一个函数以完成所有重复附加，我称此函数append_all（），并且代码变得更加清晰，更简单：

代码：

pn, tooling, up, step, dept, layer=[], [], [], [], [], []

def append_all(item_sub, st, status):
    for st in item.find('Route').find('Steps'):
        pn.append(item.findtext('CustPartNumber'))
        tooling.append(item.find('PartParameters').findtext('Value27'))
        up.append(item.findtext('UnitPerPanel'))
        step.append(st.findtext('StepNo'))
        dept.append(st.findtext('ResourceName'))
        if status == 'st':
            layer.append(item_sub.findtext('TopLevelBomPartNumber'))
        elif status == 'st2' or status == 'st3':
            layer.append(item_sub.find('PartParameters').findtext('Value113'))

for item in document.iterfind('CustomerPart'):
    append_all(item, st, 'st')
    for sub in item.find('SubAssemblies'):
        append_all(sub, st2, 'st2')
        try:
            for sub1 in sub.find('SubAssemblies'):
                append_all(sub1, st3, 'st3')  
        except :
            continue
                   
df = pd.DataFrame({'PartNumber': pn, 'tooling':tooling,'Unit Per Panel':up, 'step':step,'dept':dept,'layer':layer})