[python] How does Python return multiple values from a function?

I have written the following code:

class FigureOut:
   def setName(self, name):
      fullname = name.split()
      self.first_name = fullname[0]
      self.last_name = fullname[1]

   def getName(self):
      return self.first_name, self.last_name

f = FigureOut()
f.setName("Allen Solly")
name = f.getName()
print (name)

I get the following Output:

('Allen', 'Solly')

Whenever multiple values are returned from a function in python, does it always convert the multiple values to a list of multiple values and then returns it from the function?

Is the whole process same as converting the multiple values to a list explicitly and then returning the list, for example in JAVA, as one can return only one object from a function in JAVA?

This question is related to python function python-3.x return

The answer is


Python functions always return a unique value. The comma operator is the constructor of tuples so self.first_name, self.last_name evaluates to a tuple and that tuple is the actual value the function is returning.


mentioned also here, you can use this:

import collections
Point = collections.namedtuple('Point', ['x', 'y'])
p = Point(1, y=2)
>>> p.x, p.y
1 2
>>> p[0], p[1]
1 2

Whenever multiple values are returned from a function in python, does it always convert the multiple values to a list of multiple values and then returns it from the function??

I'm just adding a name and print the result that returns from the function. the type of result is 'tuple'.

  class FigureOut:
   first_name = None
   last_name = None
   def setName(self, name):
      fullname = name.split()
      self.first_name = fullname[0]
      self.last_name = fullname[1]
      self.special_name = fullname[2]
   def getName(self):
      return self.first_name, self.last_name, self.special_name

f = FigureOut()
f.setName("Allen Solly Jun")
name = f.getName()
print type(name)


I don't know whether you have heard about 'first class function'. Python is the language that has 'first class function'

I hope my answer could help you. Happy coding.


Here It is actually returning tuple.

If you execute this code in Python 3:

def get():
    a = 3
    b = 5
    return a,b
number = get()
print(type(number))
print(number)

Output :

<class 'tuple'>
(3, 5)

But if you change the code line return [a,b] instead of return a,b and execute :

def get():
    a = 3
    b = 5
    return [a,b]
number = get()
print(type(number))
print(number)

Output :

<class 'list'>
[3, 5]

It is only returning single object which contains multiple values.

There is another alternative to return statement for returning multiple values, use yield( to check in details see this What does the "yield" keyword do in Python?)

Sample Example :

def get():
    for i in range(5):
        yield i
number = get()
print(type(number))
print(number)
for i in number:
    print(i)

Output :

<class 'generator'>
<generator object get at 0x7fbe5a1698b8>
0
1
2
3
4

From Python Cookbook v.30

def myfun():
    return 1, 2, 3

a, b, c = myfun()

Although it looks like myfun() returns multiple values, a tuple is actually being created. It looks a bit peculiar, but it’s actually the comma that forms a tuple, not the parentheses

So yes, what's going on in Python is an internal transformation from multiple comma separated values to a tuple and vice-versa.

Though there's no equivalent in you can easily create this behaviour using array's or some Collections like Lists:

private static int[] sumAndRest(int x, int y) {
    int[] toReturn = new int[2];

    toReturn[0] = x + y;
    toReturn[1] = x - y;

    return toReturn;

}

Executed in this way:

public static void main(String[] args) {
    int[] results = sumAndRest(10, 5);

    int sum  = results[0];
    int rest = results[1];

    System.out.println("sum = " + sum + "\nrest = " + rest);

}

result:

sum = 15
rest = 5

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