Getting TypeError: unhashable type: 'list' in python dict [duplicate]

Question

I have a dictionary in python :

aDict = {
    'form-1-device': ['2'],
    'form-0-test_group': ['1'],
    'form-1-test_scenario': ['3'],
}

i need to remove the form-1-device with device and so on from dict . So far i have tried this:

for k,v in bDict.iteritems():
    newk = [k[k.find('-',5)+1:]] 
    print newk
    aDict[newk] = aDict[k]
    del aDict[k]

or instead of

 aDict[newk] = aDict[k]
 del aDict[k]

This will also do the job

aDict[newk] = aDict.pop(k)

My expected output is :

aDict = {
    'device': ['2'],
    'test_group': ['1'],
    'test_scenario': ['3'],
}

But it gives an error TypeError: unhashable type: 'list' in python dict SO far i looked in to Python dictionary : TypeError: unhashable type: 'list' and Python, TypeError: unhashable type: 'list' also had a look to this Python creating dictionary key from a list of items But nothing worked for me. Any help would be appreciated.

Its because of that dictionary keys are hashable objects and you are trying to assign an unhashable object (list) to your key. so instead of newk = [k[k.find('-',5)+1:]] do newk = k[k.find('-',5)+1:] — Kasravnd
– Kasravnd, Commented Jun 9, 2015 at 6:18

Konstantin · Accepted Answer · 2015-06-09 06:23:47Z

1

The problem is in this line

newk = [k[k.find('-',5)+1:]]

newk is a list, not a string. Remove square brackets and your code should work.

There is a good explanation why lists can't be used as dictionary keys - https://wiki.python.org/moin/DictionaryKeys

Also I would recommend you to use dictionary comprehensions to create a new dictionary and bind aDict name to it.

aDict = {
    'form-1-device': ['2'],
    'form-0-test_group': ['1'],
    'form-1-test_scenario': ['3'],
    }

aDict = {k[k.find('-',5)+1:]:v for k, v in aDict.iteritems()}

edited Jun 9, 2015 at 6:23

answered Jun 9, 2015 at 6:17

Konstantin

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1 Comment

coder3521 Over a year ago

really appreciated. Nice and pythonic.

tamasgal · Accepted Answer · 2015-06-09 06:18:48Z

0

You crate the new key here:

newk = [k[k.find('-',5)+1:]]

Which produces ['device']. That's a list (which can't be used as a dictionary key, since it is not hashable)… You need to get rid of the outer brackets:

newk = k[k.find('-',5)+1:]

answered Jun 9, 2015 at 6:18

tamasgal

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Comments

Łukasz Rogalski · Accepted Answer · 2015-06-09 06:19:09Z

0

You simply messed up creating a new key - dicts are implemented as hash-maps and requires hashable objects as their keys. You are clearly passing single-element list (square brackets around newk variable).

Is this works OK?

d = {
    'form-1-device': ['2'],
    'form-0-test_group': ['1'],
    'form-1-test_scenario': ['3'],
    }

for k,v in d.iteritems():
    new_key = k.split('-')[2]
    d[new_key] = d.pop(k)

expected = {
    'device': ['2'],
    'test_group': ['1'],
    'test_scenario': ['3'],
    }

assert d == expected

answered Jun 9, 2015 at 6:19

Łukasz Rogalski

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1 Comment

coder3521 Over a year ago

Thanks for the answer . self explanatory +1 .:)

Chakkakuru · Accepted Answer · 2015-06-09 06:21:04Z

0

Remove the square brackets from the newk assignment and use items instead of iteritems

for k,v in bDict.items():
    newk = k[k.find('-',5)+1:]
    print newk
    aDict[newk] = aDict[k]
    del aDict[k]

answered Jun 9, 2015 at 6:21

Chakkakuru

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