Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Python Collections (Retired) Dictionaries Membership

Posted by remslysambo
remslysambo
8,216 Points

Challenge Task 1 of 1 Write a function named members that takes two arguments, a dictionary and a list of keys.

Challenge Task 1 of 1

Write a function named members that takes two arguments, a dictionary and a list of keys. Return a count of how many of the items in the list are also keys in the dictionary.

Hi, i just fixed this code to pass the challenge, and i think that must be right way to do it. can somebody help please?

my_dict = {'apples': 1, 'bananas': 2, 'coconuts': 3} my_list = ['apples', 'coconuts', 'grapes', 'strawberries']

def members(my_dict, my_list): count = 1 for fruit in my_dict: for fruits in my_list: if fruit == fruits: count += 1

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

### Example
# my_dict = {'apples': 1, 'bananas': 2, 'coconuts': 3}
# my_list = ['apples', 'coconuts', 'grapes', 'strawberries']
# members(my_dict, my_list) => 2

3 Answers

remslysambo
remslysambo
8,216 Points

Thank you for your help :)

Anish Walawalkar
Anish Walawalkar
8,534 Points
Anish Walawalkar
Anish Walawalkar
8,534 Points

Hey remslysambo, here is an easier way to implement it:

def members(d, l):
  count = 0

  for item in l:
    if d.get(item, None):
      count = count + 1
  return count

Steps:

  1. loop through every item in the list l
  2. the get function of the python dictionary d takes 2 arguments, the first being the key and second being a default value to return if a value for that key is not found
  3. for example my_lsit contains "strawberries" but my_dict does not contain the key "strawberries" hence when you call d.get("strawberries", None), it will return None and count will not get incremented

Hope that helps. :)

Ary de Oliveira
Ary de Oliveira
28,298 Points

File testy25.py

def members(d, 1): count = 0

for item in 1: if d.get(item, None): count = count + 1 return count

treehouse:~/workspace$ python testy25.py

File "testy25.py", line 1

def members(d, 1):                                                
               ^
Ary de Oliveira
Ary de Oliveira
28,298 Points

File testy25.py

def members(d, 1): count = 0

for item in 1: if d.get(item, None): count = count + 1 return count

treehouse:~/workspace$ python testy25.py

File "testy25.py", line 1

def members(d, 1):                                                
               ^
Lisa Burbon
Lisa Burbon
1,030 Points
Lisa Burbon
Lisa Burbon
1,030 Points 
def members(my_dict, my_list):
  count = 0
  for item in my_dict:
    if item in my_list:
      count += 1
  return (count)