Python - printing list of dictionaries matching the values from a list-CodePudding

I have a list as ,

arr = ["rajab", "vedanth", "chinmay", "vignesh"]

and a dictionary as,

elements = [
        { 'name': 'vedanth',   'age': 17, 'time_hours': 1},
        { 'name': 'rajab', 'age': 12,  'time_hours': 3},
        { 'name': 'vignesh',  'age': 21,  'time_hours': 2.5},
        { 'name': 'chinmay',  'age': 24,  'time_hours': 1.5},
    ]

I want to print the elements in the dictionary based upon the values from the list..

Output:
elements = [       
        { 'name': 'rajab', 'age': 12,  'time_hours': 3},
       { 'name': 'vedanth',   'age': 17, 'time_hours': 1},
        { 'name': 'chinmay',  'age': 24,  'time_hours': 1.5},
        { 'name': 'vignesh',  'age': 21,  'time_hours': 2.5}
    ]

How can this be done by avoiding many for loops?

CodePudding user response：

The thing you mean is sorting, here based on the index of the name in the arr list

arr = ["rajab", "vedanth", "chinmay", "vignesh"]

elements = [
    {'name': 'vedanth', 'age': 17, 'time_hours': 1},
    {'name': 'rajab', 'age': 12, 'time_hours': 3},
    {'name': 'vignesh', 'age': 21, 'time_hours': 2.5},
    {'name': 'chinmay', 'age': 24, 'time_hours': 1.5},
]

elements.sort(key=lambda item: arr.index(item['name']))

print(elements)

CodePudding user response：

I would first construct a dict that maps name to dict and then use it:

arr = ["rajab", "vedanth", "chinmay", "vignesh"]
elements = [{ 'name': 'vedanth',  'age': 17, 'time_hours': 1},
            { 'name': 'rajab', 'age': 12, 'time_hours': 3},
            { 'name': 'vignesh', 'age': 21, 'time_hours': 2.5},
            { 'name': 'chinmay', 'age': 24, 'time_hours': 1.5}]

name_to_dict = {dct['name']: dct for dct in elements}

output = [name_to_dict[name] for name in arr]
print(output)
# [{'name': 'rajab', 'age': 12, 'time_hours': 3},
#  {'name': 'vedanth', 'age': 17, 'time_hours': 1},
#  {'name': 'chinmay', 'age': 24, 'time_hours': 1.5},
#  {'name': 'vignesh', 'age': 21, 'time_hours': 2.5}]

CodePudding user response：

newElements = [x for x in elements for y in arr if y == x['name']]