How can I get dictionary key as variable directly in Python (not by searching from value)?

Question

Sorry for this basic question but my searches on this are not turning up anything other than how to get a dictionary's key based on its value which I would prefer not to use as I simply want the text/name of the key and am worried that searching by value may end up returning 2 or more keys if the dictionary has a lot of entries... what I am trying to do is this:

mydictionary={'keyname':'somevalue'}
for current in mydictionary:

   result = mydictionary.(some_function_to_get_key_name)[current]
   print result
   "keyname"

The reason for this is that I am printing these out to a document and I want to use the key name and the value in doing this

I have seen the method below but this seems to just return the key's value

get(key[, default])

Do you just want to check that 'keyname' exists in the dictionary? Because you *do* have it already. — relet, Aug 23 '10 at 07:04
no as I said, need to print it out, it would be iterating through a large number of keys — Rick, Aug 23 '10 at 07:08
How would you get just the 1st key in the dictionary? (no iteration) — VISQL, Apr 28 '15 at 00:35

systempuntoout · Accepted Answer · 2015-08-07T13:33:38.003

269

You should iterate over keys with:

for key in mydictionary:
   print "key: %s , value: %s" % (key, mydictionary[key])

edited Aug 07 '15 at 13:33

answered Aug 23 '10 at 07:04

systempuntoout

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You can just write `for key in mydictionary:` – blokeley Jul 12 '15 at 10:27
12

in python 3.6: `print (f"key: {key}, value: {mydictionary[key]}")` – JinSnow Jan 24 '17 at 21:22

score 122 · Answer 2 · edited Oct 12 '20 at 11:19

122

If you want to access both the key and value, use the following:

Python 2:

for key, value in my_dict.iteritems():
    print(key, value)

Python 3:

for key, value in my_dict.items():
    print(key, value)

edited Oct 12 '20 at 11:19

Pikamander2

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answered Aug 23 '10 at 07:05

Escualo

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For Python 3: items() instead of iteritems() – toshiro92 Nov 15 '17 at 14:36

score 87 · Answer 3 · answered Aug 23 '10 at 07:06

87

The reason for this is that I am printing these out to a document and I want to use the key name and the value in doing this

Based on the above requirement this is what I would suggest:

keys = mydictionary.keys()
keys.sort()

for each in keys:
    print "%s: %s" % (each, mydictionary.get(each))

answered Aug 23 '10 at 07:06

Manoj Govindan

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I prefer the other answers like the for loop on `my_dict.item()` or list comprehension like `keys = list(my_dict.keys)` but just in case someone wants to do this in Python 3 : (line 2) `keys = sorted(my_dict.keys())` + add () to print. – Honiix Dec 12 '16 at 09:03

score 79 · Answer 4 · edited Feb 11 '18 at 18:32

79

If the dictionary contains one pair like this:

d = {'age':24}

then you can get as

field, value = d.items()[0]

For Python 3.5, do this:

key = list(d.keys())[0]

edited Feb 11 '18 at 18:32

Simon

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answered Jul 24 '15 at 09:39

Sudhin

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Python3.5: `TypeError: 'dict_items' object does not support indexing` – Sinux Aug 19 '16 at 02:10
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Pretty hackish but d.__iter__().__next__() does a the trick. you get 'age'. You get the same result with this d.items().__iter__().__next__()[0]. – yoshi Nov 21 '16 at 08:16
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In Python3, this works for one pair dicts: `key = list(d.keys())[0]` – Juha Untinen Dec 20 '16 at 13:24
If you have a huge dict, using `next()` is better according to: http://stackoverflow.com/a/27638751/1488445 – Juha Untinen Dec 20 '16 at 13:27
works with python 3.11 – Tech May 24 '23 at 16:47

score 14 · Answer 5 · edited Dec 30 '14 at 17:52

14

keys=[i for i in mydictionary.keys()] or keys = list(mydictionary.keys())

edited Dec 30 '14 at 17:52

Ondrej Janacek

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answered Dec 30 '14 at 17:18

kurian

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Please make sure to use code tags and explain your answer as well. – Chrismas007 Dec 30 '14 at 17:25

score 11 · Answer 6 · edited Jan 02 '19 at 20:53

11

As simple as that:

mydictionary={'keyname':'somevalue'}
result = mydictionary.popitem()[0]

You will modify your dictionary and should make a copy of it first

edited Jan 02 '19 at 20:53

cssyphus

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answered Nov 22 '16 at 03:20

Libert

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score 11 · Answer 7 · answered Nov 09 '18 at 23:40

11

You could simply use * which unpacks the dictionary keys. Example:

d = {'x': 1, 'y': 2}
t = (*d,)
print(t) # ('x', 'y')

answered Nov 09 '18 at 23:40

Georg

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python34: SyntaxError: can use starred expression only as assignment target – Tcll Jun 22 '19 at 14:44
dang, I use python34 because I can't run anything newer in my windows testing environment. – Tcll Jun 26 '19 at 12:07

score 5 · Answer 8 · answered Feb 27 '15 at 03:20

5

Iterate over dictionary (i) will return the key, then using it (i) to get the value

for i in D:
    print "key: %s, value: %s" % (i, D[i])

answered Feb 27 '15 at 03:20

splucena

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score 4 · Answer 9 · answered Nov 21 '16 at 14:48

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For python 3 If you want to get only the keys use this. Replace print(key) with print(values) if you want the values.

for key,value in my_dict:
  print(key)

answered Nov 21 '16 at 14:48

siddharth

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s3icc0 · Answer 10 · 2017-03-20T22:51:11.463

What I sometimes do is I create another dictionary just to be able whatever I feel I need to access as string. Then I iterate over multiple dictionaries matching keys to build e.g. a table with first column as description.

dict_names = {'key1': 'Text 1', 'key2': 'Text 2'}
dict_values = {'key1': 0, 'key2': 1} 

for key, value in dict_names.items():
    print('{0} {1}'.format(dict_names[key], dict_values[key])

You can easily do for a huge amount of dictionaries to match data (I like the fact that with dictionary you can always refer to something well known as the key name)

yes I use dictionaries to store results of functions so I don't need to run these functions everytime I call them just only once and then access the results anytime.

EDIT: in my example the key name does not really matter (I personally like using the same key names as it is easier to go pick a single value from any of my matching dictionaries), just make sure the number of keys in each dictionary is the same

score 2 · Answer 11 · answered Oct 24 '19 at 14:52

You can do this by casting the dict keys and values to list. It can also be be done for items.

Example:

f = {'one': 'police', 'two': 'oranges', 'three': 'car'}
list(f.keys())[0] = 'one'
list(f.keys())[1] = 'two'

list(f.values())[0] = 'police'
list(f.values())[1] = 'oranges'

score 2 · Answer 12 · answered Dec 02 '20 at 17:44

2

if you just need to get a key-value from a simple dictionary like e.g:

os_type = {'ubuntu': '20.04'}

use popitem() method:

os, version = os_type.popitem()
print(os) # 'ubuntu'
print(version) # '20.04'

answered Dec 02 '20 at 17:44

Savrige

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score 0 · Answer 13 · answered Oct 10 '21 at 22:14

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names=[key for key, value in mydictionary.items()]

answered Oct 10 '21 at 22:14

albert dellor

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score 0 · Answer 14 · answered Nov 06 '21 at 18:33

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if you have a dict like

d = {'age':24}

then you can get key and value by d.popitem()

key, value = d.popitem()

answered Nov 06 '21 at 18:33

nima

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score -2 · Answer 15 · answered Feb 15 '19 at 22:27

easily change the position of your keys and values,then use values to get key, in dictionary keys can have same value but they(keys) should be different. for instance if you have a list and the first value of it is a key for your problem and other values are the specs of the first value:

list1=["Name",'ID=13736','Phone:1313','Dep:pyhton']

you can save and use the data easily in Dictionary by this loop:

data_dict={}
for i in range(1, len(list1)):
     data_dict[list1[i]]=list1[0]
print(data_dict)
{'ID=13736': 'Name', 'Phone:1313': 'Name', 'Dep:pyhton': 'Name'}

then you can find the key(name) base on any input value.

How can I get dictionary key as variable directly in Python (not by searching from value)?

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