Assoc-in and get-in for python

util.py

# XXX maybe move this to the util module
# Let's make our lives easier with assoc-in and get-in
# From: https://stackoverflow.com/questions/10578554/equivalent-of-clojures-assoc-in-and-get-in-in-python
# with additional support for deferencing an array
def _assoc_in(dct, path, value, sep=':'):
    """In a dictionary dct, using the path (which is a 
    <sep>-separated string) assign the resulting key to value,
    overwriting it if its present. If it encounters an iterable and the current
    path component is an integer, operates on that.
    """
    for x in path.split(sep):
        if x.isdigit():
            if isinstance(dct, list):
                prev, dct = dct, dct[int(x)]
            else:
                prev, dct = dct, dct.setdefault(x, {})
        else:
            prev, dct = dct, dct.setdefault(x, {})
    prev[x] = value

def _get_in(dct, path, sep=':'):
    """In a dictionary dct, using the path (which is a 
    <sep>-separated string) get the resulting key's value"""
    for x in path.split(sep):
        if x.isdigit():
            if isinstance(dct, list):
                prev, dct = dct, dct[int(x)]
            else:
                prev, dct = dct, dct[x]                
        else:
            prev, dct = dct, dct[x]
    return prev[x]