我实际上已经找到了一个解决方案，但它涉及全局变量，并且没有返回语句。我想知道是否有更好的办法。基本上，我做了一个递归函数来搜索注册表项，我希望它在找到匹配项时返回“key”对象。
这是我的第一次尝试：

import winreg
import sys

def parse_reg(key,find_subkey=" ",find_value=" "):
    try:
        num_subkeys = winreg.QueryInfoKey(key)[0]       #queries number of subkeys for this key
        for i in range(num_subkeys):                    
            sub_keys = winreg.EnumKey(key,i)            #gets the subkey name from index i
            sub_key = winreg.OpenKeyEx(key,sub_keys)        #subkey object from the subkey name
            num_values = winreg.QueryInfoKey(sub_key)[1]        
            for j in range(num_values):                     #this for statement iterates through the values of the subkey
                sub_values = winreg.EnumValue(sub_key,j)
                print("-"*len(sub_keys)+sub_values[0]+": "+str(sub_values[1]))
                if str(sub_values[1]) == find_value:
                    return sub_key
            print(sub_keys)
            if find_subkey in sub_keys:
                return sub_key
            parse_reg(sub_key,find_subkey,find_value)       #call the function again, this time with the new subkey
    except PermissionError as e:
        pass

reg = winreg.ConnectRegistry(None,winreg.HKEY_LOCAL_MACHINE)
key = winreg.OpenKeyEx(reg,r"System\CurrentControlSet\Enum")    
key2 =parse_reg(key,"VID_2C7C&PID_0121&MI_03")
print(key2)                 #prints None

我没有意识到递归函数返回到它自己，所以这不起作用。
尝试2，使用参数解除递归函数调用：

import winreg
import sys

def parse_reg(key,_return,find_subkey=" ",find_value=" "):
    if _return !=None:
        sub_key = ""
        return parse_reg(sub_key,_return,find_subkey,find_value)  #tried this and return _return
    try:
        num_subkeys = winreg.QueryInfoKey(key)[0]       #queries number of subkeys for this key
        for i in range(num_subkeys):                    
            sub_keys = winreg.EnumKey(key,i)            #gets the subkey name from index i
            sub_key = winreg.OpenKeyEx(key,sub_keys)        #subkey object from the subkey name
            num_values = winreg.QueryInfoKey(sub_key)[1]        
            for j in range(num_values):                     #this for statement iterates through the values of the subkey
                sub_values = winreg.EnumValue(sub_key,j)
                print("-"*len(sub_keys)+sub_values[0]+": "+str(sub_values[1]))
                if str(sub_values[1]) == find_value:
                    _return =sub_key
            print(sub_keys)
            if find_subkey in sub_keys:
                _return= sub_key
            parse_reg(sub_key,_return,find_subkey,find_value)       #call the function again, this time with the new subkey
    except PermissionError as e:
        pass

reg = winreg.ConnectRegistry(None,winreg.HKEY_LOCAL_MACHINE)
key = winreg.OpenKeyEx(reg,r"System\CurrentControlSet\Enum")    
key2 =parse_reg(key,None,"VID_2C7C&PID_0121&MI_03")
print(key2)

这一个永远叫它自己。如果我有 return _return 它的问题与第一个解决方案相同。
最后，我决定只使用一个全局变量。

import winreg
import sys

def parse_reg(key,_return,find_subkey=" ",find_value=" "):
    try:
        num_subkeys = winreg.QueryInfoKey(key)[0]
        for i in range(num_subkeys):
            sub_keys = winreg.EnumKey(key,i)
            sub_key = winreg.OpenKeyEx(key,sub_keys)
            num_values = winreg.QueryInfoKey(sub_key)[1]
            for j in range(num_values):
                sub_values = winreg.EnumValue(sub_key,j)
                print("-"*len(sub_keys)+sub_values[0]+": "+str(sub_values[1]))
                if str(sub_values[1]) == find_value:
                    global key2
                    key2 = sub_key
            print(sub_keys)
            if find_subkey in sub_keys:
                print(sub_keys,find_subkey)
                print("FOUND")
                print(dir(sub_key))
                global key2
                key2=sub_key
            parse_reg(sub_key,_return,find_subkey,find_value)
    except PermissionError as e:
        pass

reg = winreg.ConnectRegistry(None,winreg.HKEY_LOCAL_MACHINE)
key = winreg.OpenKeyEx(reg,r"System\CurrentControlSet\Enum")
parse_reg(key,None,"VID_2C7C&PID_0121&MI_03")
print(key2,"hello")

我知道必须有一种方法来回报价值，但我被难住了。任何帮助都将不胜感激！！：）