How to access a class object inside a list when a value for one of the class attributes is given in Python?

Question

I have a list of class objects and I want to know how can I print a particular class object inside the list given a value for one of its attributes.

Here is my code:

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age

lst = [Person("A",1), Person("B",2), Person("C", 3)]

inputAge = int(input("Age: "))

if inputAge == 2:
  print() #this should print the class object with age 2 from the list 

I don't know what should I put inside the print() code.

Answer 1

This is how you can find the first element of the list having a specific attribute (precondition: all objects of the list have that attribute):

obj = next((x for x in lst if x.age == inputAge), None)

obj is None if such an object can't be found in the list.

Once you found the object, you can do whatever you want with it, including printing (print(obj)).

If you want the printing of the object to be meaningful you would have to do something like this:

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age
  def __str__(self):
    return 'name: ' + self.name + ' age: ' + self.age

This is the complete example:

class Person:
  def __init__(self, name, age):
    self.name = name
    self.age = age
  def __str__(self):
    return 'name: ' + self.name + ' age: ' + self.age

lst = [Person("A",1), Person("B",2), Person("C", 3)]

inputAge = int(input("Age: "))
obj = next((x for x in lst if x.age == inputAge), None)
print(obj) # prints the object with age = inputAge