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![Noor Hafiza Binti Ibrahim](https://secure.gravatar.com/avatar/f8ae750659a67f12ae55b4e930b99641?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Noor Hafiza Binti Ibrahim
11,712 Pointsi'm absolutely lost on this one. how do i use the filter lambda() here? another solution?
Bummer: TypeError: filter expected 2 arguments, got 1
# {
# 'name': 'Javier Hernandez',
# 'pets': [
# {
# 'name': 'Kitty',
# 'breed': 'American Shorthair'
# },
# {
# 'name': 'Buzz',
# 'breed': 'Pitbull'
# }
# ],
# 'classes': ('Math', 'Science', 'Art')
# }
# enter your code below
def breeds(data):
return list(filter(lambda item: item.get('breed')))
1 Answer
![Chris Freeman](https://uploads.teamtreehouse.com/production/profile-photos/1153532/micro_image.jpg)
Chris Freeman
Treehouse Moderator 68,425 PointsHey Noor Hafiza Binti Ibrahim, That's a really neat question. I haven't see a solution using filter
, so let's dig into it!
Let's fix the first error. The builtin filter function takes two arguments, the second (missing) argument is the iterable object.
Let's try data
:
filter(lambda item: item.get('breed'), data)
If we use the data
object passed in, it will fail because. using data
in a interable context will just return the keys of the dictionary. This causes an error because the first key "name" is a string which does not have the get()
method:
AttributeError: 'str' object has no attribute 'get'
Let's go deeper and try the list found at data["pets"]
filter(lambda item: item.get('breed'), data["pets"]))
This also fails since filter is simply looking for a "true" result. Since "breed" is a valid key to each dictionary in data["pets"]
, the entire dictionary is returned. This is equivalent to:
for item in data["pets"]:
if item.get('breed'):
print(item) # entire item
# results:
# {'name': 'Kitty', 'breed': 'American Shorthair'}
# {'name': 'Buzz', 'breed': 'Pitbull'}
What will work is to use map instead of filter
. This will return the result of the lambda and not the whole object.
map(lambda item: item.get('breed'), data["pets"]))
This works because it returns the result of each get. This is equivalent to:
for item in data["pets"]:
if item.get('breed'):
print(item.get('breed')) # the breed value
# results:
American Shorthair
Pitbull
Post back if you need more help. Good luck!!
Noor Hafiza Binti Ibrahim
11,712 PointsNoor Hafiza Binti Ibrahim
11,712 PointsWOW, thank u so much. it was very helpful