list1 = [a,b,c]
list2 =[d,e,f]
list3 = [g,h,j]
new_list = []

for i in list1:
    new_dev ={'key1':'value1','key2':'value2','key3':i}
    new_list.append(new_dev)

I want to perform the same action as above and iterate over list2 and list3 and there values should reflect in key1 from list1 and key2 from list2. Thus after appending into the empty list 'new_list', it will have three dictionaries as elements. Please help me resolving this.

Think of the elements of the list as the values in the dictionary and so for key1 the values should be from list1 and for key2 the values should be from list2 and so on. Thus we should be getting a list with three dictionaries as elements in the "new_list".

CodePudding user response：

You can use zip() to merge the lists, and then take three elements from the merged list at each iteration step like so:

list1 = ['a', 'b', 'c']
list2 = ['d', 'e', 'f']
list3 = ['g', 'h', 'j']
new_list = []

for (i, j, k) in zip(list1, list2, list3):
    new_dev ={'key1': i, 'key2': j, 'key3': k}
    new_list.append(new_dev)

print(new_list)

>>> [{'key1': 'a', 'key2': 'd', 'key3': 'g'}, {'key1': 'b', 'key2': 'e', 'key3': 'h'}, {'key1': 'c', 'key2': 'f', 'key3': 'j'}]

CodePudding user response：

To iterate over multiple lists and create a list of dictionaries with values from each list, you can use the following approach:

1. Create a nested loop to iterate over the lists. The outer loop will iterate over the lists, and the inner loop will iterate over the elements in each list.

2. Use the loop variables to access the elements from each list and create a dictionary with the values.

3. Append the dictionary to the new_list list.

Here is an example of how you can implement this approach:

list1 = ['a','b','c']
list2 = ['d','e','f']
list3 = ['g','h','j']
new_list = []

# outer loop to iterate over the lists
for l1, l2, l3 in zip(list1, list2, list3):
    # create a dictionary with the values
    new_dev = {'key1': l1, 'key2': l2, 'key3': l3}
    # append the dictionary to the new_list
    new_list.append(new_dev)

print(new_list)

This will create a list with three dictionaries as elements, with the values from each list being used as the values in the dictionaries. The resulting list will be:

[{'key1': 'a', 'key2': 'd', 'key3': 'g'}, {'key1': 'b', 'key2': 'e', 'key3': 'h'}, {'key1': 'c', 'key2': 'f', 'key3': 'j'}]

CodePudding user response：

You can do this with a one-liner using two zips in a list comprehension -

list1 = ['a','b','c']
list2 = ['d','e','f']
list3 = ['g','h','j']

keys = ['key1','key2','key3']                                #<----
out = [dict(zip(keys,i)) for i in zip(list1, list2, list3)]  #<----

print(out)

[{'key1': 'a', 'key2': 'd', 'key3': 'g'},
 {'key1': 'b', 'key2': 'e', 'key3': 'h'},
 {'key1': 'c', 'key2': 'f', 'key3': 'j'}]

EXPLANATION

1. First you zip(list1, list2, list3) the 3 lists together which combines the first, second, third and nth elements of each list together into respective tuples.
2. Next, you iterate through these tuples using [i for i in (list1, list2, list3)
3. After that you zip this tuple, with the list of keys using zip(keys,i), which gives you something like (key1, a), (key2, d), (key3, g) for each tuple.
4. Finally you convert this zip object to a dict using dict(zip(keys,i) which converts the first elements of each tuple as key and second elements of each tuple as value.