Why list(dict.keys()) does not work?

[landlord1984]

dict={'a':'aaa','b':'bbb','c':'ccc'}

list(dict.keys())

TypeError                                 Traceback (most recent call last)
<ipython-input-60-be97bb392967> in <module>()
----> 1 list(dict.keys())

TypeError: 'list' object is not callable

I want to get a list of the keys of a dictionary for further manipulation. But don't know why this does not work. Somebody here:http://stackoverflow.com/questions/17322...t-indexing
suggested they can do by this way, but it does not work for me.

Another question is: Can I access dictionary by index instead of key?

Thanks,

L

[wavic]

Hello!
First, do not use keywords as variable names. I mean dict.

You can call list() built-in in the interpreter but in a script, you have to assign list() returns to a variable or use it as a callback.

The interpreter:

In [1]: dict={'a':'aaa','b':'bbb','c':'ccc'}

In [2]: list(dict.keys())
Out[2]: ['b', 'a', 'c']

In script:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

my_dict = {'a':'aaa','b':'bbb','c':'ccc'}

l = list(my_dict.keys())

print(l)
print(my_dict.keys())

Output:

Output:
['a', 'c', 'b']
['a', 'c', 'b']

[Ofnuts]

dict={'a':'aaa','b':'bbb','c':'ccc'}

list(dict.keys())

TypeError                                 Traceback (most recent call last)
<ipython-input-60-be97bb392967> in <module>()
----> 1 list(dict.keys())

TypeError: 'list' object is not callable

I want to get a list of the keys of a dictionary for further manipulation. But don't know why this does not work. Somebody here:http://stackoverflow.com/questions/17322...t-indexing
suggested they can do by this way, but it does not work for me.

Another question is: Can I access dictionary by index instead of key?

Thanks,

L

That should work. Since you use dict which is a type name as a variable, I can assume that you have a list variable elwhere in your code, that hides the list() function.

No, you cannot access a dictionary by index. You can at best access the keys by index and then use the keys to access the values. But the key order can change if you add something to the dictionary.

[landlord1984]

my_dict = {'a':'aaa','b':'bbb','c':'ccc'}

l = list(my_dict.keys())

print(l)
print(my_dict.keys())

Weird....The script code works. But those in console still does not return "TypeError: 'list' object is not callable". Anyway, I am writing in a script, jsut sometimes do quick testing in console

---

dict={'a':'aaa','b':'bbb','c':'ccc'} list(dict.keys())

TypeError Traceback (most recent call last) <ipython-input-60-be97bb392967> in <module>() ----> 1 list(dict.keys()) TypeError: 'list' object is not callable

I want to get a list of the keys of a dictionary for further manipulation. But don't know why this does not work. Somebody here:http://stackoverflow.com/questions/17322...t-indexing suggested they can do by this way, but it does not work for me. Another question is: Can I access dictionary by index instead of key? Thanks, L

That should work. Since you use dict which is a type name as a variable, I can assume that you have a list variable elwhere in your code, that hides the list() function. No, you cannot access a dictionary by index. You can at best access the keys by index and then use the keys to access the values. But the key order can change if you add something to the dictionary.

Ok. I see. I think a need to give up using dictionary in this case. I want to do some manipulation of insert and remove.

[snippsat]

But the key order can change if you add something to the dictionary.

Before 3.6 this is true,but not after  

Another question is: Can I access dictionary by index instead of key?

It can work with 3.6,but if you should do it is an other case

>>> d = {'a':'aaa','b':'bbb','c':'ccc'}
>>> d
{'a': 'aaa', 'b': 'bbb', 'c': 'ccc'}

>>> lst = list(d.keys())
>>> lst
['a', 'b', 'c']

# Index will match dict because in 3.6 are dict ordered 
>>> d[lst[2]]
'ccc'

# Add something and the order do not change
>>> d['d'] = 'ddd'
>>> d
{'a': 'aaa', 'b': 'bbb', 'c': 'ccc', 'd': 'ddd'}

>>> d.update({'e': 'eee'})
>>> d
{'a': 'aaa', 'b': 'bbb', 'c': 'ccc', 'd': 'ddd', 'e': 'eee'}

[Larz60+]

A less elegant solution using nested dict that can be used with any python version:

item_dict = {
    '1': {
        'Item': 'Widgets',
        'Unit': 'each',
        'QtyPerUnit': 1,
        'PricePerUnit': 14.25
    },
    '2': {
        'Item': 'Wigs',
        'Color': ['red', 'brown', 'white'],
        'Unit': 'each',
        'QtyPerUnit': 1,
        'PricePerUnit': 5.25
    },
    '3': {
        'Item': 'fountain drink',
        'Size': ['small', 'medium', 'large'],
        'Unit': 'Ounces',
        'QtyPerUnit': 16,
        'PricePerUnit': 1.95
    }
}

merchandise = list(item_dict.keys())
merchandise.sort()
print('merchandise: {}'.format(merchandise))
print('item_dict 1: {}'.format(item_dict['1']))

results:

Output:
merchandise: ['1', '2', '3']
item_dict 1: {'PricePerUnit': 14.25, 'Item': 'Widgets', 'QtyPerUnit': 1, 'Unit': 'each'}