CODEWITHSUNDEEP
pythondictionary
user3112327
user3112327

Reputation: 305

How to reset all values in a dictionary

{"green": 0, "y3": 1, "m@tt": 0, "newaccount": 0, "egg": 0, "results": 0, "dan": 0, "Lewis": 0, "NewAccount2": 0, "testyear3": 1, "testyear6": 0, "NewAccount1": 0, "testyear4": 0, "testyear5": 0, "Matt1": 0, "swag": 1, "lewis": 1, "matt": 1, "notin": 0}

this is the dictionary defined as 'completeddict'. What I want to do, is to change ALL values no matter what they are called to 0. However bear in mind that new account names will be added at any point as 'keys' so I cannot manually do "completeddict[green] = 0", "completeddict[lewis] = 0", etc etc.

Is there any way to have python change ALL values within a dictionary back to 0?

EDIT: Unfortunately I do not want to create a new dictionary - I want to keep it called 'completeddict' as the program needs to use the dictionary defined as 'completeddict' at many points in the program.

Upvotes: 13

Views: 47823

Answers (7)

Paul
Paul

Reputation: 7335

I had a similar situation where the dictionary could itself have nested dictionary and list values and all values that were not of type dictionary/list needed to be set to a default value:

def Clear(e1,defaultValue):
  if type(e1) is dict:
    return {k:Clear(e1[k], defaultValue) for k in e1.keys()}
  elif type(e1) is list:
    return [Clear(v,defaultValue) for v in e1]
  else:
    return defaultValue

Upvotes: 0

Harpreet
Harpreet

Reputation: 11

completeddict.clear() should reset the entries. Check Python Docs.

Upvotes: 0

alecxe
alecxe

Reputation: 474131

Another option is to use .fromkeys():

fromkeys(seq[, value])

Create a new dictionary with keys from seq and values set to value.

d = d.fromkeys(d, 0)

Demo:

>>> d = {"green": 0, "y3": 1, "m@tt": 0, "newaccount": 0, "egg": 0, "results": 0, "dan": 0, "Lewis": 0, "NewAccount2": 0, "testyear3": 1, "testyear6": 0, "NewAccount1": 0, "testyear4": 0, "testyear5": 0, "Matt1": 0, "swag": 1, "lewis": 1, "matt": 1, "notin": 0}
>>> d.fromkeys(d, 0)
{'newaccount': 0, 'swag': 0, 'notin': 0, 'NewAccount1': 0, 'Matt1': 0, 'testyear4': 0, 'Lewis': 0, 'dan': 0, 'matt': 0, 'results': 0, 'm@tt': 0, 'green': 0, 'testyear5': 0, 'lewis': 0, 'NewAccount2': 0, 'y3': 0, 'testyear3': 0, 'egg': 0, 'testyear6': 0}

Upvotes: 44

surendra
surendra

Reputation: 21

Adding to alecxe asnwer,

your dictionary is,

completeddict = {"green": 0, "y3": 1, "m@tt": 0, "newaccount": 0, "egg": 0, "results": 0, "dan": 0, "Lewis": 0, "NewAccount2": 0, "testyear3": 1, "testyear6": 0, "NewAccount1": 0, "testyear4": 0, "testyear5": 0, "Matt1": 0, "swag": 1, "lewis": 1, "matt": 1, "notin": 0}

now this dictionary can be updated with default values, 

completeddict.update({}.fromkeys(completeddict,0)

Done. your completeddict is updated with default value for all keys.

Ex:

a = {'x':2,'y':4}
print id(a)  
print a
a.update({}.fromkeys(a,0))
print id(a)
print a

Output:

42612608     <--- id of dict 'a'
{'y': 4, 'x': 2}     <--- dict 'a' before updation
42612608     <--- id of dict 'a'   
{'y': 0, 'x': 0}     <--- dict 'a' after updation

It can be observed that id of the dictionary same even after it is updated with default values.

Upvotes: 2

Bryan Oakley
Bryan Oakley

Reputation: 386295

If you don't want to create a new dict, it seems like all you need is a simple two-line loop, unless I'm missing something:

for key in completeddict.keys():
    completeddict[key] = 0

Upvotes: 7

dawg
dawg

Reputation: 104072

A form that will work in virtually any Python version is just use the dict constructor with a list comprehension or generator:

>>> d={"green": 10, "y3": 11, "m@tt": 12, "newaccount": 22, "egg": 55, "results": 0, "dan": 0, "Lewis": 0, "NewAccount2": 0, "testyear3": 1, "testyear6": 0, "NewAccount1": 0, "testyear4": 0, "testyear5": 0, "Matt1": 0, "swag": 1, "lewis": 1, "matt": 1, "notin": 0}
>>> d=dict((k, 0) for k in d)
>>> d
{'newaccount': 0, 'swag': 0, 'notin': 0, 'NewAccount1': 0, 'Matt1': 0, 'testyear4': 0, 'Lewis': 0, 'dan': 0, 'matt': 0, 'results': 0, 'm@tt': 0, 'green': 0, 'testyear5': 0, 'lewis': 0, 'NewAccount2': 0, 'y3': 0, 'testyear3': 0, 'egg': 0, 'testyear6': 0}

Which you can then use with a mutable argument or some form of callable:

>>> d=dict((k, list()) for k in d)

Now each element of d is a new list (or whatever else mutable or not you would want to set the value portion of the tuple to be).

Upvotes: 5

wnnmaw
wnnmaw

Reputation: 5534

Sure, its pretty easy:

newDict = {key: 0 for key in completeddict}

This is dictionary comprehension and is equivalent to:

newDict = {}
for key in completeddict:
    newDict[key] = 0

These dict comprehensions were introduced in v2.7, so older vesions will need to use the expanded form.

Upvotes: 15

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