Python: How to pass key to a dictionary from the variable of a function?

Question

Basically I have two dictionaries: one is a Counter() the other is dict()

The first one contains all the unique words in a text, as keys and each words' frequency in the text, as the values

The second contains the same unique words as keys, but the values are the definitions which are user-inputted.

The latter is what I'm having trouble implementing. I created a function which takes in a word, checks if that word is in the frequency dictionary, and if it is, allows the user to input a definition of that word (else, it will print an error). The word and its definition are then added to the second dictionary as a key-value pair (using dict.update(word=definition)).

But whenever I run the program I get the error:

Nameerror: name '' is not defined

Here is the code:

import string
import collections
import pickle

freq_dict = collections.Counter()
dfn_dict = dict()

def cleanedup(fh):
    for line in fh:
        word = ''
        for character in line:
            if character in string.ascii_letters:
                word += character
            else:
                yield word
                word = ''

def process_book(textname):
    with open (textname) as doc:
        freq_dict.update(cleanedup(doc))
    global span_freq_dict
    span_freq_dict = pickle.dumps(freq_dict)


def show_Nth_word(N):
    global span_freq_dict
    l = pickle.loads(span_freq_dict)
    return l.most_common()[N]

def show_N_freq_words(N):    
    global span_freq_dict
    l = pickle.loads(span_freq_dict)
    return l.most_common(N)

def define_word(word):
    if word in freq_dict:
        definition = eval(input('Please define ' + str(word) + ':'))
        dfn_dict({word: definition})
    else:
        return print('Word not in dictionary!')



process_book('DQ.txt')
process_book('HV.txt')

# This was to see if the if/else was working
define_word('asdfs')
#This is the actual word I want to add
define_word('de')

print(dfn_dict.items())

I get the feeling that either the error is very small or very big. Any help would be greatly appreciated.

EDIT: So the program now allows me to enter a definition, but returns this error once I do so:

>>> 
Word not in dictionary!
Please define esperar:To await
Traceback (most recent call last):
  File "C:\Users\User 3.1\Desktop\Code Projects\dict.py", line 50, in <module>
    define_word('esperar')
  File "C:\Users\User 3.1\Desktop\Code Projects\dict.py", line 37, in define_word
    definition = eval(input('Please define ' + str(word) + ':'))
  File "<string>", line 1
    To await
           ^
SyntaxError: unexpected EOF while parsing
>>> 

Solution

dict.update(word=definition) won’t do what you think it does. See this example:

>>> someDict = {}
>>> word = 'foo'
>>> definition = 'bar'
>>> someDict.update(word=definition)
>>> someDict
{'word': 'bar'}

As you can see, this method will always update the key word although you want the word variable to be resolved first. This won’t work though because you are passing a named argument to the update function, and those named arguments are taken literally.

If you want to update the key that equals to the value of word, you can just do it like this:

someDict[word] = definition

Comments

[Dider]

Thanks, but unfortunately, upon updating the code to use this method I get either a Syntax error (on the "=" symbol). Or (if I delete "return" and just leave it as dfn_dict[word]=definition) a Nameerror again (same as before)

[poke]

Yes, you can’t do return dfn_dict[word] = definition. You would have to split that into two lines, e.g. dfn_dict[word] = definition and then return dfn_dict. But since you are modifying the global dfn_dict anyway (btw. no need to call global here), you don’t actually need to return it.

[Dider]

Nope, still getting the same NameError

[Riccardo]

@ShihabDider i execute this code and it works, are you sure you replaced input to raw_input? or also to eval(input(..))?

[Dider]

I was mistaken earlier, its not the same NameError, it now says: Name 'raw_input' is not defined. Also I've edited the OP with updated code

[Dider]

EDIT: I tried using eval(input()) the NameError is gone, but now in its place is: SyntaxError unxpected EOF while parsing (see OP for full details)

[poke]

@ShihabDider eval(input('Please define ' + str(word) + ':')) You definitely want to drop the eval there.

[Riccardo]

@ShihabDider which version of Python are you using?

[Dider]

Having done this, I now get dfn_dict({word: definition}) TypeError: 'dict' object is not callable

[Dider]

I'm using Python 3.4.1

[poke]

@ShihabDider Please read the answer again? You are trying something completely different now.

[Dider]

Thanks so much! You were totally right, I changed the key update part, back to your suggestion and it now works perfectly. I just realized I forgot the .update attribute.