Why always need this "get" methods?

Question

class teste(object):
    def __init__(self,a):
        self.a=a

    def getA(self):
        return self.a



new=teste("lucas")
print new.getA()  #########  LINE 1
print new.a       #########  LINE 2

Why in classes we always need this "get" methods? i mean, what's the difference between the "LINE 1" and "LINE 2"? they output the same thing.

Nobody needs "get" methods. Get rid of them. If you must do some calculations or hide things, use `property` — JBernardo, Feb 21 '13 at 21:29
You need setter and getter methods in languages that have private variables, like C++ and Java, but you don't need them in python. — Akavall, Feb 21 '13 at 21:32
As a side note, you probably don't want to call your object `new`, because that's the name of a standard library module. (That's no longer true in 3.x, but it may still lead to confusion among long-time Python users—and automated syntax highlighters, as you can see from the way your code was highlighted here.) — abarnert, Feb 21 '13 at 21:51
Who told you you always need get methods? Did you read it somewhere?? — John La Rooy, Feb 21 '13 at 21:55

score 4 · Accepted Answer · edited May 23 '17 at 12:10

4

You don't in Python.

Note that getters and setters are frequently considered "unpythonic" (related: python -c 'import this').

Getters are just a style. Sometimes you might want to use a getter but it is not always necessary. See why use getters and setters for a sort of general discussion on getters and setters.

For more relevancy to Python, consider:
An opinion piece, another opinion piece, some sample code or some other sample code.

edited May 23 '17 at 12:10

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answered Feb 21 '13 at 21:32

William

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First, it's just a style—but a style that's generally considered non-pythonic. Unnecessary getters will raise a red flag in readers of your code who are familiar with Python. – abarnert Feb 21 '13 at 21:49
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Also, those links are more appropriate Java-like languages—in particular, most of the advantages in the accepted answer to the SO question aren't relevant in Python (while many of the disadvantages in the comments are…). But of course you already gave the Python answer in your first sentence of your answer, so that's not a big problem. – abarnert Feb 21 '13 at 21:49
You are right, and I was just actually looking for some Python-specific links (I updated the answer with some Python links) – William Feb 21 '13 at 22:02
Nice link on attempting to define "pythonic". – abarnert Feb 21 '13 at 22:10

score 3 · Answer 2 · answered Feb 21 '13 at 21:29

3

In python you don't need get methods. It is a matter of coding style.

answered Feb 21 '13 at 21:29

matt snider

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score 1 · Answer 3 · edited May 23 '17 at 12:17

The other answers already say that you never need getters in Python, and it's just a matter of style.

But the key here is that there is a Pythonic style, and unnecessary getters go against that style. Using unnecessary getters will raise red flags when experienced Python developers read your code. (How many seconds did it take to get three comments saying variations of "Someone used Java too much" here?)

If you read the PEP 8 style guide, under Designing for inheritance, it says:

For simple public data attributes, it is best to expose just the attribute name, without complicated accessor/mutator methods. Keep in mind that Python provides an easy path to future enhancement, should you find that a simple data attribute needs to grow functional behavior. In that case, use properties to hide functional implementation behind simple data attribute access syntax.

PEP 8 is only intended as a style guide for the stdlib, but it's still generally considered a good description of what idiomatic Python looks like ("TOOWTDI" means any descriptive guide is implicitly a prescriptive guide, at least in theory), and there are nice testers and fixers that let you test your own code against PEP 8 guidelines.

While I'm at it, William's answer linked to why use getters and setters, a language-agnostic question, where the accepted answer is a list of reasons why accessors are sometimes a good idea. Almost none of them are relevant to Python. Most can be answered with one word: @property (or, in the last case, attrgetter). For the rest:

Controlling the lifetime and memory management… Python has managed memory.
Providing a debugging interception point… Interpreted languages make it easy to place watchpoints while debugging.
Improved interoperability with libraries… Python's mock, pickle, etc. are designed to operate with attributes.
Allowing inheritors to change the semantics of how the property behaves and is exposed by overriding the getter/setter methods. This is only relevant for languages with static typing except for virtual functions, like C++ or Java.

score 0 · Answer 4 · answered Feb 21 '13 at 21:31

You don't need to use "get" methods, the only difference in your example is that if you use new.a you can assign it a new value.

So if you intend to have a read only attribute then a get method is appropriate. (note that if the method returns a mutable object, you can modify that object, so not technically read only)

score 0 · Answer 5 · edited May 23 '17 at 11:54

0

Normally in Python we just use normal attribute access. If you decide you need "getters" and "setters" later on, you can easily turn those into properties. You don't need to clutter up your code "just in case"

One imporant point to me is that you don't need to change any code that uses the class when you do this.

edited May 23 '17 at 11:54

Community

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answered Feb 21 '13 at 21:52

John La Rooy

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Why always need this "get" methods?

5 Answers5