Way to print dictionary as a list [duplicate]

Question

So I have a dictionary which is like -

 {'gaining': 34, 'Tinga': 42, 'small': 39, 'legs,': 13,}.

Is there a way in which i can print it out so that it becomes a list like -

 [ gaining, Tinga, small, legs ]

So that only the keys are printed and not the values that go along it. Also is there a way to make the dictionary not work in arbitrary order - such that if two keys are repeated instead of giving it the value of the last one, we give it the value of the first one?

eg;

 {'gaining' : 34, 'Tinga' : 42, 'small : 39, 'legs,' : 13 'gaining' : 20}

When printed

 print dict['gaining']

The output comes as

instead of coming as

Duplicate key is not a problem. It is just the way dictionaries work. — Stephen Rauch
– Stephen Rauch ♦, Commented Jan 20, 2017 at 6:30
It looks like you want us to write some code for you. While many users are willing to produce code for a coder in distress, they usually only help when the poster has already tried to solve the problem on their own. A good way to demonstrate this effort is to include the code you've written so far, example input (if there is any), the expected output, and the output you actually get (output, tracebacks, etc.). The more detail you provide, the more answers you are likely to receive. Check the FAQ and How to Ask. — TigerhawkT3
– TigerhawkT3, Commented Jan 20, 2017 at 6:33

Mad Physicist · Accepted Answer · 2017-01-20 06:55:15Z

Printing the keys is straightforward. In Python 3:

d = {'gaining': 34, 'Tinga': 42, 'small': 39, 'legs,': 13,} print(list(d.keys()))

In Python 2, dict.keys already returns a list instead of a special view object, so you can do

print d.keys()

You can set values in a dict without overwriting previous keys using the setdefault method. This method sets the value of a key only if it is not already present in the dict. The only catch is that it only handles one key at a time, so you would need to put it in a loop or do it sequentially:

d.setdefault('gaining', 34) d.setdefault('Tinga', 42) d.setdefault('small', 39) d.setdefault('legs', 13) d.setdefault('gaining', 20) print (d['gaining']) 34

OR

i = [('gaining', 34), ('Tinga', 42), ('small', 39), ('legs', 13), ('gaining', 20)] for k, v in i: d.setdefault(k, v)

airstrike · Accepted Answer · 2017-01-20 06:34:53Z

Dictionaries can't have two identical keys by definition. You should read the python docs to understand how they really work.

To answer your question:

d = {'gaining': 34, 'Tinga': 42, 'small': 39, 'legs': 13} d.keys()

which will return

dict_keys(['legs', 'gaining', 'Tinga', 'small'])

If you really want to print them in the exact format you specified:

print('[' + ', '.join(d.keys()) + ']')

which will return

[legs, gaining, Tinga, small]

Note that dictionaries are unsorted by definition, so the exact output may vary.

How is [k for k in d.keys()] different from d.keys() or list(d.keys())?
@DYZ I guess it isn't but could make it easier to adapt it to other print formats?

kouty · Accepted Answer · 2017-01-20 08:15:25Z

dict.keys() would suffice to achieve the first thing you asked.

Your second question is a bit tricky. You see, dictionaries store key value pairs, and there is this notion that a dictionary has unique keys. So, you can not put multiple values corresponding to a key in the manner you described.

Instead, what you can do is defining each value in the dict to be a list, and appending new values for a key to the list for that key. (i.e. dict[key]) Then, when you try to read a random value of a key, you can pick a random value from the list dict[key].

zenprogrammer · Accepted Answer · 2017-01-20 06:30:44Z

-3

This will get you keys in a list

keyList = [x for x,y in d.items()]

answered Jan 20, 2017 at 6:30

zenprogrammer

7511 gold badge7 silver badges21 bronze badges

3 Comments

user5653854 Over a year ago

... or just use .keys()

DYZ Over a year ago

That's called d.keys().

zenprogrammer Over a year ago

yes that's obvious :) only giving another option to poster to get more understanding about dictionaries, lists and iteration.

Collectives™ on Stack Overflow

Way to print dictionary as a list [duplicate]

4 Answers 4

Comments

2 Comments

Comments

3 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

2 Comments

Comments

3 Comments

Linked

Related