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Python Python Collections (Retired) Dictionaries Membership

Siddhant Shrivastav
Siddhant Shrivastav
17,320 Points

Can someone please explain why this code throws an error?

I understand that looping through the dictionary and conditionally checking the list for common key values is the better way to do it. I'd just like some input on why this way is not working as I expected it to.

# You can check for dictionary membership using the
# "key in dict" syntax from lists.

### Example

def members(a_dict, a_list):
  count = 0
  for items in a_list:
    if items == a_dict[items]:
      count += 1
  return count    

my_dict = {'apples': 1, 'bananas': 2, 'coconuts': 3}
my_list = ['apples', 'coconuts']
members(my_dict, my_list)

1 Answer

Hanley Chan
Hanley Chan
27,771 Points


Your if condition appears to be incorrect. For example in your example list and dictionary during the first iteration of your for loop the variable items would be 'apples'. Your if condition would then check if 'apples' == a_dict['apples'], but a_dict['apples'] = 1. So you are comparing if 'apples' == 1.