How to change which class variable is being called depending on user input?

Question

I've created a class called Earthquake which stores relevant earthquake data (its magnitude, time it hit, etc.) in class variables. I want to ask the user which data they'd like to see, then print out that data for them like so:

earthquake1 = Earthquake()

answer = input("What data would you like to see?")
print(earthquake1.answer)

In the example above, if the user answers magnitude, I want to print out the class variable earthquake1.magnitude.

Is there some way of doing this?

Probably getattr... also easily done with eval but eval is evil — A.J. Uppal
– A.J. Uppal, Commented Aug 29, 2016 at 3:22
@dfasoro I'd rather not use if statements because I've got over 20 attributes — Ash
– Ash, Commented Aug 29, 2016 at 3:29
Ok, @A.J. 's answer below should suffice, I will suggest you sanitize/filter the input in case you have some attributes (asides the 20) in the earthquake object you don't necessarily want the user to see. — dfasoro
– dfasoro, Commented Aug 29, 2016 at 3:32
How do Earthquake instances know about what earthquake they're about? — martineau
– martineau, Commented Aug 29, 2016 at 4:12

A.J. Uppal · Accepted Answer · 2016-08-29 03:22:04Z

4

Just use getattr:

earthquake1 = Earthquake()

answer = input("What data would you like to see?")
print(getattr(earthquake1, answer))

answered Aug 29, 2016 at 3:22

A.J. Uppal

19.3k7 gold badges47 silver badges82 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Dimitris Fasarakis Hilliard · Accepted Answer · 2016-08-29 03:21:31Z

2

You could use getattr which is equivalent to earthquake.attr_name. The difference is that getattr allows you to use a variable to access the name and supply a default value if that is not found.

In short:

 print(getattr(earthquake1, answer))

Or, if you need to use a default value instead of raising a KeyError:

print(getattr(earthquake1, answer, "Instance variable {} not found".format(answer)))

answered Aug 29, 2016 at 3:21

Dimitris Fasarakis Hilliard

162k35 gold badges282 silver badges265 bronze badges

Collectives™ on Stack Overflow

How to change which class variable is being called depending on user input?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related