I'm receiving a dict from one "layer" of code upon which some calculations/modifications are performed before passing it onto another "layer". The original dict's keys & "string" values are unicode
, but the layer they're being passed onto only accepts str
.
This is going to be called often, so I'd like to know what would be the fastest way to convert something like:
{ u'spam': u'eggs', u'foo': True, u'bar': { u'baz': 97 } }
...to:
{ 'spam': 'eggs', 'foo': True, 'bar': { 'baz': 97 } }
...bearing in mind the non-"string" values need to stay as their original type.
Any thoughts?
DATA = { u'spam': u'eggs', u'foo': frozenset([u'Gah!']), u'bar': { u'baz': 97 },
u'list': [u'list', (True, u'Maybe'), set([u'and', u'a', u'set', 1])]}
def convert(data):
if isinstance(data, basestring):
return str(data)
elif isinstance(data, collections.Mapping):
return dict(map(convert, data.iteritems()))
elif isinstance(data, collections.Iterable):
return type(data)(map(convert, data))
else:
return data
print DATA
print convert(DATA)
# Prints:
# {u'list': [u'list', (True, u'Maybe'), set([u'and', u'a', u'set', 1])], u'foo': frozenset([u'Gah!']), u'bar': {u'baz': 97}, u'spam': u'eggs'}
# {'bar': {'baz': 97}, 'foo': frozenset(['Gah!']), 'list': ['list', (True, 'Maybe'), set(['and', 'a', 'set', 1])], 'spam': 'eggs'}
Assumptions:
data.encode('utf-8')
rather than str(data)
if you need an explicit encoding).If you need to support other container types, hopefully it's obvious how to follow the pattern and add cases for them.
for a non-nested dict (since the title does not mention that case, it might be interesting for other people)
{str(k): str(v) for k, v in my_dict.items()}
If you wanted to do this inline and didn't need recursive descent, this might work:
DATA = { u'spam': u'eggs', u'foo': True, u'bar': { u'baz': 97 } }
print DATA
# "{ u'spam': u'eggs', u'foo': True, u'bar': { u'baz': 97 } }"
STRING_DATA = dict([(str(k), v) for k, v in data.items()])
print STRING_DATA
# "{ 'spam': 'eggs', 'foo': True, 'bar': { u'baz': 97 } }"
To make it all inline (non-recursive):
{str(k):(str(v) if isinstance(v, unicode) else v) for k,v in my_dict.items()}
def to_str(key, value):
if isinstance(key, unicode):
key = str(key)
if isinstance(value, unicode):
value = str(value)
return key, value
pass key and value to it, and add recursion to your code to account for inner dictionary.
Just use print(*(dict.keys()))
The * can be used for unpacking containers e.g. lists. For more info on * check this SO answer.
I know I'm late on this one:
def convert_keys_to_string(dictionary):
"""Recursively converts dictionary keys to strings."""
if not isinstance(dictionary, dict):
return dictionary
return dict((str(k), convert_keys_to_string(v))
for k, v in dictionary.items())
>>> d = {u"a": u"b", u"c": u"d"}
>>> d
{u'a': u'b', u'c': u'd'}
>>> import json
>>> import yaml
>>> d = {u"a": u"b", u"c": u"d"}
>>> yaml.safe_load(json.dumps(d))
{'a': 'b', 'c': 'd'}
Source: Stackoverflow.com