CODEWITHSUNDEEP
python
Bala
Bala

Reputation: 19

Python list and dictionary

How do I access dictionaries inside a list?

c = [{'team':2000,'name':'a'}, {'team':3000,'name':'b'}]
values = []
for key, value in c.iteritems():
    values.append((key, value))
    print values

I tried accessing the list using iteritems but I got an error specifying list does not have iteritems. Then, I tried using a for loop but I still get an error specifying list indices must be integers.

Upvotes: 0

Views: 101

Answers (3)

Merlin
Merlin

Reputation: 25639

Try this: 

c = [{'team':2000,'name':'a'}, {'team':3000,'name':'b'}]
values = []
for row in c: 
    for key, value in row.iteritems():
         if key == 'name': 
             values.append((key, value))
print(values)

# gives this
# [('name', 'a'),  ('name', 'b'),]

Upvotes: 1

Will
Will

Reputation: 24699

I'm not sure what your desired output is, but the problem is that c is a list() of dict()s, not a dict(). So if you want to loop over every key and value in each dict in the list, you need two loops:

In [85]: for dictionary in c:
   ....:     for key, value in dictionary.iteritems():
   ....:         values.append((key, value))
   ....:         print values
   ....:
[('name', 'a')]
[('name', 'a'), ('team', 2000)]
[('name', 'a'), ('team', 2000), ('name', 'b')]
[('name', 'a'), ('team', 2000), ('name', 'b'), ('team', 3000)]

You can also simplify this with a list comprehension:

In [96]: for dictionary in c:
    values.extend((key, value) for key, value in dictionary.iteritems())
   ....:

In [97]: values
Out[97]: [('name', 'a'), ('team', 2000), ('name', 'b'), ('team', 3000)]

Or, simplify it even further, as list.extend() can take any iterable:

In [112]: for dictionary in c:
    values.extend(dictionary.iteritems())
   .....:

In [113]: values
Out[113]: [('name', 'a'), ('team', 2000), ('name', 'b'), ('team', 3000)]

And, lastly, we can populate values with a single line of code using itertools.chain(), which basically "flattens" multiple iterables into a single iterable (thanks @lvc!):

In [114]: from itertools import chain

In [115]: values = list(chain.from_iterable(d.iteritems() for d in c))

Upvotes: 2

COCO
COCO

Reputation: 158

"c" is not a dictionary therefore iteritems() will not work. Iterate through the list first to isolate the dictionaries. 

>>> c = [{'team':2000,'name':'a'}, {'team':3000,'name':'b'}]
... for i in c:
...     for k,v in i.items():
...         print "key : "+str(k)+' *** '+ "value : "+str(v)

... key : name *** value : a
... key : team *** value : 2000
... key : name *** value : b
... key : team *** value : 3000

Upvotes: 0

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