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Sort object list by one or multiple attributes in normal or reverse order in python3
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| from operator import attrgetter | |
| def sort_by_attr(alist, *args): | |
| """ | |
| Sort an object list by one or more of its atributes | |
| Parameters: | |
| alist (list): object list | |
| *args (strings): the name of one or more of the objects attributes | |
| possibly preceded by a '-' sign to use reversed order | |
| Example: | |
| sort_by(user_list, "name", "-age") | |
| """ | |
| for fname in reversed(args): | |
| # Remove order modifier from field name | |
| reverse = (fname[0] == '-') | |
| fname = fname[1:] if fname[0] in ("+", "-") else fname | |
| # Sort by field name in selected order | |
| alist.sort(key=attrgetter(fname), reverse=reverse) | |
| # An example | |
| ############# | |
| class User(object): | |
| def __init__(self, name, age): | |
| self.name = name | |
| self.age = age | |
| def __repr__(self): | |
| return "<User {} {}>".format(self.name, self.age) | |
| users = [User('john', 44), User('lisa', 22), User('anna', 22), User('peter', 77)] | |
| sort_by_attr(users, "name") | |
| print("name:\t", users) | |
| sort_by_attr(users, "-name") | |
| print("-name:\t", users) | |
| sort_by_attr(users, "age") | |
| print("age:\t", users) | |
| sort_by_attr(users, "-age") | |
| print("-age:\t", users) | |
| sort_by_attr(users, "name", "age") | |
| print("name age:\t", users) | |
| sort_by_attr(users, "age", "name") | |
| print("age name:\t", users) | |
| sort_by_attr(users, "age", "-name") | |
| print("age -name:\t", users) | |
| sort_by_attr(users, "-age", "name") | |
| print("-age name:\t", users) |
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