How to get value from list of dictionaries based on specific key value which does not exist in all dictionaries?

Question

I have a list of dictionaries that is like this:

{'name': ['Sam'], 'where': ['London']},
{'name': ['Jon'], 'where': ['NY']},
{'name': ['Jon'], 'hobby': ['fifa']},
{'Age': ['20'], 'Country': ['US']},

I do have a dictionary like this that could have a lot of same keys but a lot doesn't have that key too. As in above example, we have name key in first 3, but we don't have name key in the 4th. I am trying to get a list of all values that has key 'name'.

Thanks

mozway · Accepted Answer · 2022-10-04 18:26:20Z

1

What you want is unclear (nor the link to pandas or numpy).

If you simply want the values of name when those exist:

l = [{'name': ['Sam'], 'where': ['London']},
     {'name': ['Jon'], 'where': ['NY']},
     {'name': ['Jon'], 'hobby': ['fifa']},
     {'Age': ['20'], 'Country': ['US']},]

out = [d['name'] for d in l if 'name' in d]
# [['Sam'], ['Jon'], ['Jon']]

# or as flat list
out = [name for d in l if 'name' in d for name in d['name']]
# ['Sam', 'Jon', 'Jon']

# or just the first name
out = [d['name'][0] for d in l if 'name' in d]
# ['Sam', 'Jon', 'Jon']

answered Oct 4, 2022 at 18:26

mozway

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4 Comments

python_pi Over a year ago

Thanks. However, I am getting this error: argument of type 'NoneType' is not iterable

mozway Over a year ago

Do you have a None in the list? please provide a reproducible list for which this error happens

python_pi Over a year ago

there are errors in the list as well: This is some part form list of dictionary: ------------------------------------------------------------------- 0 {'select': ['all_cons_columns.column_name'], '... 1 {'select': ['free_mb'], 'where': ['name']} 2 {'insert': ['sessionid', 'entryid', 'statement... 3 error:MERGE /*+ OPT_PARAM('_parallel_syspls_ob... 4 error:MERGE /*+ OPT_PARAM('_parallel_syspls_ob... ----------------------------------------------------------------------- I am trying to get value paired with select key

mozway Over a year ago

I can't help you without a reproducible input.

Robert Haas · Accepted Answer · 2022-10-04 18:26:05Z

0

Here is a way to extract all names:

data = [
    {'name': ['Sam'], 'where': ['London']},
    {'name': ['Jon'], 'where': ['NY']},
    {'name': ['Jon'], 'hobby': ['fifa']},
    {'Age': ['20'], 'Country': ['US']},
]

names = [item['name'][0] for item in data if 'name' in item]
print(names)

Result:

['Sam', 'Jon', 'Jon']

answered Oct 4, 2022 at 18:26

Robert Haas

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Comments

bitflip · Accepted Answer · 2022-10-04 18:27:23Z

0

I assume your data is a list of dicts.

data = [{'name': ['Sam'], 'where': ['London']},
{'name': ['Jon'], 'where': ['NY']},
{'name': ['Jon'], 'hobby': ['fifa']},
{'Age': ['20'], 'Country': ['US']},]

You can get a sub list of all elements with a name key like this:

output = [elem for elem in data if elem.get("name")]

answered Oct 4, 2022 at 18:27

bitflip

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4 Comments

python_pi Over a year ago

Thanks for your input, I get this error: AttributeError: 'NoneType' object has no attribute 'get'

bitflip Over a year ago

Do you have a None in your input? Try this please output = [elem for elem in data if elem and elem.get("name")]

python_pi Over a year ago

there were None, I removed them using: aaa= {k: v for k, v in df_1_joins_where.items() if v is not None} however now i get this error as I use that code: argument of type 'int' is not iterable

bitflip Over a year ago

seems like your data is not in the same format as your example data

jackal · Accepted Answer · 2022-10-04 18:28:38Z

0

There are many ways to do this. One would be:

_list = [{'name': ['Sam'], 'where': ['London']},
{'name': ['Jon'], 'where': ['NY']},
{'name': ['Jon'], 'hobby': ['fifa']},
{'Age': ['20'], 'Country': ['US']}]

print(*(name for d in _list if (name := d.get('name'))))

Output:

['Sam'] ['Jon'] ['Jon']

answered Oct 4, 2022 at 18:28

jackal

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Comments

userE · Accepted Answer · 2022-10-04 18:29:44Z

0

You can try a list expression:

all_dicts = [{'name': ['Sam'], 'where': ['London']},
{'name': ['Jon'], 'where': ['NY']},
{'name': ['Jon'], 'hobby': ['fifa']},
{'Age': ['20'], 'Country': ['US']}]

dicts_with_name = [d.values() for d in all_dicts if 'name' in d.keys() ]

This extracts all values (for all keys) of those dictionaries in the list that have a name field. If you want the key, value pairs, you can d.items() instead of d.values()

answered Oct 4, 2022 at 18:29

userE

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