Python - Apply member function in a map

Question

I declare a class Employee and a list consist of it:

class Employee():
    def __init__(self, _name):
        self.name = _name
    def get_name(self):
        return self.name

Tom   = Employee("Tom")
Karl  = Employee("Karl")
John  = Employee("John")

employee_list = [Tom, Karl, John]

Now I want to have a list of their name by applying get_name in a map:

name_list = map(get_name, employee_list)


Traceback (most recent call last): File "ask.py", line 13, in <module> 
    name_list = map(get_name, employee_list) 
NameError: name 'get_name' is not defined

How could get_name be not defined?

How do I do to apply member function in a map?

Answer 1

map(get_name, employee_list)in your code is equivalent to

[get_name(employee) for employee in employee_list]

not [employee.get_name() for employee in employee_list]

You should declare a get_name method outside of Employee class:

def get_name(employee):
    return employee.name

or an easier way with Lambda:

name_list = map(lambda employee: employee.name, employee_list)

Answer 2

You have to call the method from the instance. You can use a lambda for this

name_list = map(lambda e: e.get_name(), employee_list)