How can I get list of values from dict?
You can use * operator to unpack dict_values:
>>> d = {1: "a", 2: "b"}
>>> [*d.values()]
['a', 'b']
or list object
>>> d = {1: "a", 2: "b"}
>>> list(d.values())
['a', 'b']
Follow the below example --
songs = [
{"title": "happy birthday", "playcount": 4},
{"title": "AC/DC", "playcount": 2},
{"title": "Billie Jean", "playcount": 6},
{"title": "Human Touch", "playcount": 3}
]
print("====================")
print(f'Songs --> {songs} \n')
title = list(map(lambda x : x['title'], songs))
print(f'Print Title --> {title}')
playcount = list(map(lambda x : x['playcount'], songs))
print(f'Print Playcount --> {playcount}')
print (f'Print Sorted playcount --> {sorted(playcount)}')
# Aliter -
print(sorted(list(map(lambda x: x['playcount'],songs))))
dict.values
returns a view of the dictionary's values, so you have to wrap it in list
:
list(d.values())
There should be one ‒ and preferably only one ‒ obvious way to do it.
Therefore list(dictionary.values())
is the one way.
Yet, considering Python3, what is quicker?
[*L]
vs. [].extend(L)
vs. list(L)
small_ds = {x: str(x+42) for x in range(10)}
small_df = {x: float(x+42) for x in range(10)}
print('Small Dict(str)')
%timeit [*small_ds.values()]
%timeit [].extend(small_ds.values())
%timeit list(small_ds.values())
print('Small Dict(float)')
%timeit [*small_df.values()]
%timeit [].extend(small_df.values())
%timeit list(small_df.values())
big_ds = {x: str(x+42) for x in range(1000000)}
big_df = {x: float(x+42) for x in range(1000000)}
print('Big Dict(str)')
%timeit [*big_ds.values()]
%timeit [].extend(big_ds.values())
%timeit list(big_ds.values())
print('Big Dict(float)')
%timeit [*big_df.values()]
%timeit [].extend(big_df.values())
%timeit list(big_df.values())
Small Dict(str)
256 ns ± 3.37 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
338 ns ± 0.807 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
336 ns ± 1.9 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
Small Dict(float)
268 ns ± 0.297 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
343 ns ± 15.2 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
336 ns ± 0.68 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
Big Dict(str)
17.5 ms ± 142 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
16.5 ms ± 338 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
16.2 ms ± 19.7 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
Big Dict(float)
13.2 ms ± 41 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
13.1 ms ± 919 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
12.8 ms ± 578 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
Done on Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz.
# Name Version Build
ipython 7.5.0 py37h24bf2e0_0
The result
- For small dictionaries
* operator
is quicker - For big dictionaries where it matters
list()
is maybe slightly quicker