TypeError: unhashable type: 'dict', when dict used as a key for another dict

python json hash
Frias picture Frias · Dec 25, 2010 · Viewed 163.3k times · Source

I have this piece of code:

for element in json[referenceElement].keys():

When I run that code, I get this error:

TypeError: unhashable type: 'dict'

What is the cause of that error and what can I do to fix it?

Answer

moinudin picture moinudin · Dec 25, 2010

From the error, I infer that referenceElement is a dictionary (see repro below). A dictionary cannot be hashed and therefore cannot be used as a key to another dictionary (or itself for that matter!).

>>> d1, d2 = {}, {}
>>> d1[d2] = 1
Traceback (most recent call last):
  File "<input>", line 1, in <module>
TypeError: unhashable type: 'dict'

You probably meant either for element in referenceElement.keys() or for element in json['referenceElement'].keys(). With more context on what types json and referenceElement are and what they contain, we will be able to better help you if neither solution works.

Related questions

Why can't Python parse this JSON data?

I have this JSON in a file: { "maps": [ { "id": "blabla", "iscategorical": "0" }, { "id": "blabla", "iscategorical": "0" } ], "masks": [ "id": "valore" ], "om_points": "value", "parameters": [ "id": "valore" ] } I wrote this script to print all of the JSON data: import json from pprint import pprint …

Read More
How do I write JSON data to a file?

I have JSON data stored in the variable data. I want to write this to a text file for testing so I don't have to grab the data from the server each time. Currently, I am trying this: obj = open(…

Read More
How to prettyprint a JSON file?

I have a JSON file that is a mess that I want to prettyprint. What's the easiest way to do this in Python? I know PrettyPrint takes an "object", which I think can be a file, but I don't know …

Read More