Question

I need a function to change one item in composite dictionary.
I’ve tried something like..

def SetItem(keys, value):

    item = self.dict

    for key in keys:          
        item = item[key]

    item = value

and

 SetItem(['key1', 'key2'], 86)

It should be equivalent to self.dict[‘key1’][‘key2’] = 86, but this function has no effect.

Answer 1

Almost. You actually want to do something like:

def set_keys(d, keys, value):
    item = d
    for key in keys[:-1]:
        item = item[key]
    item[keys[-1]] = value

Or recursively like this:

def set_key(d, keys, value):
    if len(keys) == 1:
        d[keys[0]] = value
    else:
        set_key(d[keys[0]], keys[1:], value)

Marcin’s right though. You would really want to incorporate something more rigorous, with some error handling for missing keys/missing dicts.