Python Key Error=0 - Can't Find Dict Error in Code

Python Key Error=0 - Can't find Dict error in code

The error you're getting is that self.adj doesn't already have a key 0. You're trying to append to a list that doesn't exist yet.

Consider using a defaultdict instead, replacing this line (in __init__):

self.adj = {}

with this:

self.adj = defaultdict(list)

You'll need to import at the top:

from collections import defaultdict

Now rather than raise a KeyError, self.adj[0].append(edge) will create a list automatically to append to.

KeyError: 0 python with python dict

EDIT:
Fixed my error by creating a list which is appended each key to be removed which is then passed to this function:

def Aliens():
    global aliens
    clean = list()
    for i in aliens.keys():
        if(aliens[i][0] == (-100, -100) or aliens[i][1] < 0):
             clean.append(i)
    cleanAliens(clean)

and

def cleanAliens(cleanList):
    global aliens
    for i in range(len(cleanList)):
            aliens.pop(cleanList[i]);

I'm getting Key error in python

A KeyError generally means the key doesn't exist. So, are you sure the path key exists?

From the official python docs:

exception KeyError

Raised when a mapping (dictionary) key is not found in the set of
existing keys.

For example:

>>> mydict = {'a':'1','b':'2'}
>>> mydict['a']
'1'
>>> mydict['c']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'c'
>>>

So, try to print the content of meta_entry and check whether path exists or not.

>>> mydict = {'a':'1','b':'2'}
>>> print mydict
{'a': '1', 'b': '2'}

Or, you can do:

>>> 'a' in mydict
True
>>> 'c' in mydict
False

Python KeyError: 0 when working with dictionary and functions

At the end of the function, result should look like this: {'cro': X, 'eng': Y}, where X and Y are numbers. I don't know what your dictionaries are, so I can't guess what the numbers are. Evaluating result['eng'] will produce a number, as will result['cro'], but there is no 0 key in this dictionary.

Further, the second indexing operation will also give you issues. result['eng'][0] will give you an error because result['eng'] is a number, and you can't index into a number.

What do you expect the output of this function to look like? Where is sort defined and what is it supposed to do?

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