将列表项与字典键进行比较，如果该项存在于字典中，则打印出键的值

Question

Example code:

my_dict = {'ABC':'Apple','DEF':'Mango','GHI':'Pear','JKL':'Orange','MNO':'Plum'}
lst_x =  ['DEF','GHI']

Expected result:

['Mango', 'Pear']

Answer 1

You can retrieve multiple keys at once, by using operator.itemgetter :

from operator import itemgetter

my_dict = {'ABC':'Apple','DEF':'Mango','GHI':'Pear','JKL':'Orange','MNO':'Plum'}

lst_x = ['DEF','GHI']
# in case, if there's a chance, that lst_x would get some of the keys, that are not in my_dict - add the below line:
# lst_x=set(lst_x).intersection(set(my_dict.keys()))
res=itemgetter(*lst_x)(my_dict)

Outputs:

>>> res

('Mango', 'Pear')

Answer 2

You can use a simple loop, ask if there is a key with the same value and print it, for example:

my_dict = {'ABC':'Apple','DEF':'Mango','GHI':'Pear','JKL':'Orange','MNO':'Plum'}
lst = ['ABC','DEF','GHI','JKL','MNO']

for key in lst:
    if key in my_dict.keys():
        print(key, '->' , my_dict[key])

>>> ABC -> Apple
>>> DEF -> Mango
>>> GHI -> Pear
>>> JKL -> Orange
>>> MNO -> Plum

Answer 3

One approach would be to use a list comprehension to construct the requested list.
Essentially we iterate through the list in the outer loop, and through the dictionary in the inner loop and then we compare the list value with the key from the dictionary , and should we have a match, then we save the value of the associated key in the new output list.

This code snippet below works as described above:

my_dict = {'ABC':'Apple','DEF':'Mango','GHI':'Pear','JKL':'Orange','MNO':'Plum'}
lst_x = ['DEF','GHI']

out = [value for element in lst_x for key, value in my_dict.items() if element == key]
print(out)

When run it prints:

['Mango', 'Pear']

Answer 4

I personally don't believe in giving outright answers so I will give you a hint:

// for x in lst: 
//   if x in dictionary then
//     lst_x.append(x)

I believe that should be enough for you to figure out the rest.