使用while循环从函数返回变量

Question

I am new to Python, thus apologize in advance! I am trying to return two lists from a function with a while loop that reads an xml file. I can't figure out how to do it. I am referring to imres (integer) and subres (2 integers) in the code below, that are found ~10 times in the loop. Debuging shows that the variables are properly filled in the loop, but I don't know how to return the filled lists and I get the empty lists instead. Thanks.

def getresolution(node):
    imres = []
    subres = []
    child4 = node.firstChild
    while child4:
                ...
        for child8 in keepElementNodes(child7.childNodes):
            if child8.getAttribute('Hash:key') == 'ImageSize':
                X = float(child8.getElementsByTagName('Size:width')[0].firstChild.data)
                Y = float(child8.getElementsByTagName('Size:height')[0].firstChild.data)
                imres += [[X, Y]]
            if child8.getAttribute('Hash:key') == 'Resolution':
                subres += [int(child8.firstChild.data)]
        getresolution(child4)
        child4 = child4.nextSibling
    return [imres, subres]


[imres, subres] = getresolution(xml_file)

Answer 1

Not tested but this should point you in the right direction:

def getresolution(node):
    imres = []
    subres = []
    child4 = node.firstChild
    while child4:
                ...
        for child8 in keepElementNodes(child7.childNodes):
            if child8.getAttribute('Hash:key') == 'ImageSize':
                X = float(child8.getElementsByTagName('Size:width')[0].firstChild.data)
                Y = float(child8.getElementsByTagName('Size:height')[0].firstChild.data)
                imres += [[X, Y]]
                if child8.getAttribute('Hash:key') == 'Resolution':
                    subres += [int(child8.firstChild.data)]
        t_imres, t_subres = getresolution(child4)
        imres += t_imres
        subres += t_subres
        child4 = child4.nextSibling
    return [imres, subres]


[imres, subres] = getresolution(xml_file)