Get a list of values from a list of dictionaries?

Question

I have a list of dictionaries, and I need to get a list of the values from a given key from the dictionary (all the dictionaries have those same key).

For example, I have:

l = [ { "key": 1, "Val1": 'val1 from element 1', "Val2": 'val2 from element 1' }, { "key": 2, "Val1": 'val1 from element 2', "Val2": 'val2 from element 2' }, { "key": 3, "Val1": 'val1 from element 3', "Val2": 'val2 from element 3' } ]

I need to get 1, 2, 3.

Of course, I can get it with:

v=[] for i in l: v.append(i['key'])

But I would like to get a nicer way to do so.

do they all definitely have the key?

Padraic Cunningham
– Padraic Cunningham

2014-07-30 15:34:12 +00:00
Commented Jul 30, 2014 at 15:34 — Padraic Cunningham
– Padraic Cunningham, Commented Jul 30, 2014 at 15:34

vaultah · Accepted Answer · 2015-02-24 20:34:59Z

11

Using a simple list comprehension (if you're sure every dictionary has the key):

In [10]: [d['key'] for d in l] Out[10]: [1, 2, 3]

Otherwise you'll need to check for existence first:

In [11]: [d['key'] for d in l if 'key' in d] Out[11]: [1, 2, 3]

edited Feb 24, 2015 at 20:34

answered Jul 30, 2014 at 15:31

vaultah

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2 Comments

Lix Over a year ago

One line... Or less ;)

Jester Over a year ago

That's what I was looking for, doing it on a single line. Will test it, thank you.

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