Menu
Importing from JSON can get very complex and nested structures. For example:
{u'body': [{u'declarations': [{u'id': {u'name': u'i', u'type': u'Identifier'}, u'init': {u'type': u'Literal', u'value': 2}, u'type': u'VariableDeclarator'}], u'kind': u'var', u'type': u'VariableDeclaration'}, {u'declarations': [{u'id': {u'name': u'j', u'type': u'Identifier'}, u'init': {u'type': u'Literal', u'value': 4}, u'type': u'VariableDeclarator'}], u'kind': u'var', u'type': u'VariableDeclaration'}, {u'declarations': [{u'id': {u'name': u'answer', u'type': u'Identifier'}, u'init': {u'left': {u'name': u'i', u'type': u'Identifier'}, u'operator': u'*', u'right': {u'name': u'j', u'type': u'Identifier'}, u'type': u'BinaryExpression'}, u'type': u'VariableDeclarator'}], u'kind': u'var', u'type': u'VariableDeclaration'}], u'type': u'Program'} What is the recommended way to walk complex structures like the above?
Apart of a few list there are mostly dictionaries, the structure can become even more imbricated so I need a general solution.
592
You can loop through a dictionary by using a for loop. When looping through a dictionary, the return value are the keys of the dictionary, but there are methods to return the values as well.
A dictionary can contain any object type except another dictionary. Items are accessed by their position in a dictionary. Items are accessed by their position in a dictionary. Dictionaries can be nested to any depth.
You can use a recursive generator for converting your dictionary to flat lists.
def dict_generator(indict, pre=None): pre = pre[:] if pre else [] if isinstance(indict, dict): for key, value in indict.items(): if isinstance(value, dict): for d in dict_generator(value, pre + [key]): yield d elif isinstance(value, list) or isinstance(value, tuple): for v in value: for d in dict_generator(v, pre + [key]): yield d else: yield pre + [key, value] else: yield pre + [indict] It returns
[u'body', u'kind', u'var'] [u'init', u'declarations', u'body', u'type', u'Literal'] [u'init', u'declarations', u'body', u'value', 2] [u'declarations', u'body', u'type', u'VariableDeclarator'] [u'id', u'declarations', u'body', u'type', u'Identifier'] [u'id', u'declarations', u'body', u'name', u'i'] [u'body', u'type', u'VariableDeclaration'] [u'body', u'kind', u'var'] [u'init', u'declarations', u'body', u'type', u'Literal'] [u'init', u'declarations', u'body', u'value', 4] [u'declarations', u'body', u'type', u'VariableDeclarator'] [u'id', u'declarations', u'body', u'type', u'Identifier'] [u'id', u'declarations', u'body', u'name', u'j'] [u'body', u'type', u'VariableDeclaration'] [u'body', u'kind', u'var'] [u'init', u'declarations', u'body', u'operator', u'*'] [u'right', u'init', u'declarations', u'body', u'type', u'Identifier'] [u'right', u'init', u'declarations', u'body', u'name', u'j'] [u'init', u'declarations', u'body', u'type', u'BinaryExpression'] [u'left', u'init', u'declarations', u'body', u'type', u'Identifier'] [u'left', u'init', u'declarations', u'body', u'name', u'i'] [u'declarations', u'body', u'type', u'VariableDeclarator'] [u'id', u'declarations', u'body', u'type', u'Identifier'] [u'id', u'declarations', u'body', u'name', u'answer'] [u'body', u'type', u'VariableDeclaration'] [u'type', u'Program'] UPDATE: Fixed keys list from [key] + pre to pre + [key] as mentioned in comments.
73
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
