Python tuples

 A tuple is a list that can no longer be changed.

Create a tuple

To create a tuple , you can use the following syntax:

>>>  my_tuple  =  ()

Add a value to a tuple

To create a tuple with values, you can do it this way:

>>>  my_tuple  =  ( 1 ,  "ok" ,  "olive tree" )

The parentheses are not mandatory but facilitate the readability of the code (remember that the strength of python is its ease of reading):

>>>  my_tuple  =  1 ,  2 ,  3 
>>>  type ( my_tuple ) 
< type  'tuple' >

When you create a tuple with a single value, remember to add a comma to it, otherwise it is not a tuple.

>>>  my_tuple  =  ( "ok" ) 
>>>  type ( my_tuple ) 
< type  'str' > 
>>>  my_tuple  =  ( "ok" ,) 
>>>  type ( my_tuple ) 
< type  'tuple' >

Display a value of a tuple

The tuple is kind of a list, so we can use the same syntax to read data from the tuple.

>>>  my_tuple [ 0 ] 
1

And obviously if we try to change the value of an index, the interpreter insults us copiously:

>>>  mon_tuple [ 1 ]  =  "ok" 
Traceback  ( most  recent  call  last ): 
  File  "<stdin>" ,  line  1 ,  in  < module > 
TypeError :  'tuple'  object  does  not  support  item  assignment

What is a tuple for then?

The tuple allows multiple assignment:

>>>  v1 ,  v2  =  11 ,  22 
>>>  v1 
11 
>>>  v2 
22

It also allows you to return several values ​​when calling a function:

>>>  def  give_me_your_name (): 
...      return  "olivier" ,  "engel" 
...  
>>>  give_me_your_name () 
( 'olivier' ,  'engel' )

We will use a tuple to define kinds of constants which are therefore not intended to change.