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== 3.5#h(0.6em)Tuple basics


  
    
=== Learning objectives


    By the end of this section you should be able to


    - Describe the features and benefits of a tuple.
- Develop a program that creates and uses a tuple successfully.
- Identify and discuss the mutability of a tuple.


  
  
    
=== Creating tuples and accessing elements


    A #strong[tuple] is a sequence of comma separated values that can contain elements of different types. A tuple must be created with commas between values, and conventionally the sequence is surrounded by parentheses. Each element is accessed by index, starting with the first element at index 0.


    #figure(table(
  columns: 2, align: left, inset: 6pt,
  [tuple\_1 = (2, 3, 4)
print(f'tuple\_1: {tuple\_1}')
print(tuple\_1\[1\])
print()
data\_13 = ('Aimee Perry', 96, \[94, 100, 97, 93\])
print(f'data\_13: {data\_13}')
print(data\_13\[2\])], [tuple\_1: (2, 3, 4)
3

data\_13: ('Aimee Perry', 96, \[94, 100, 97, 93\])
\[94, 100, 97, 93\]],
))


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Creating tuples and accessing elements]
]


  
  
    
=== Tuple properties


    How do tuples compare to lists? Tuples are ordered and allow duplicates, like lists, but have different mutability. An #strong[immutable] object cannot be modified after creation. A #strong[mutable] object can be modified after creation. Tuples are immutable, whereas lists are mutable.


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Mutability of a tuple vs. a list]


      #link("https://www.openstax.org/r/mutability-tuple-list")[Mutability of a tuple vs. a list; ch 3, video 6]
]


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Using tuples]
]


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Mutability and performance]


      Tuples are immutable and have a fixed size, so tuples use less memory. Overall, tuples are faster to create and access, resulting in better performance that can be noticeable with large amounts of data.
]


  
  #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Creating a tuple from a list]


    Suppose a programmer wants to create a tuple from a list to prevent future changes. The tuple() function creates a tuple from an object like a list. Ex: my\_tuple = tuple(my\_list) creates a tuple from the list my\_list. Update the program below to create a tuple final\_grades from the list grades.


    grades = \[68, 77, 81, 73\]
grades\[0\] += 5

print(f'final\_grades: {final\_grades} is a {type(final\_grades)}')
]


  #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Creating a tuple with user input]


    Write a program that reads in two strings and two integers from input and creates a tuple, my\_data, with the four values.


    Given input:


    
    x
    y
    15
    20
    The output is:


    
    my\_data: ('x', 'y', 15, 20)
    \# Read input and create my\_data

print(f'my\_data: {my\_data}')
]