# 5.3 Tuples¶

### Creating Tuples¶

- To create an empty tuple, use empty parentheses.

In [1]:

    student_tuple = ()

In [2]:

    student_tuple

Out[2]:

    ()

In [3]:

    len(student_tuple)

Out[3]:

    0

- Pack a tuple by separating its values with commas.

In [4]:

    student_tuple = 'John', 'Green', 3.3

In [5]:

    student_tuple

Out[5]:

    ('John', 'Green', 3.3)

In [6]:

    len(student_tuple)

Out[6]:

    3

- When you output a tuple, Python always displays its contents in parentheses.
- Parentheses are optional when creating a tuple.

In [7]:

    another_student_tuple = ('Mary', 'Red', 3.3)

In [8]:

    another_student_tuple

Out[8]:

    ('Mary', 'Red', 3.3)

- A comma is required to create a one-element tuple.

In [9]:

    a_singleton_tuple = ('red',)  # note the comma

In [10]:

    a_singleton_tuple

Out[10]:

    ('red',)

### Accessing Tuple Elements¶

- You generally access tuple elements directly rather than iterating over them.

In [11]:

    time_tuple = (9, 16, 1)

In [12]:

    time_tuple

Out[12]:

    (9, 16, 1)

In [13]:

    time_tuple[0] * 3600 + time_tuple[1] * 60 + time_tuple[2]

Out[13]:

    33361

### Adding Items to a String or Tuple¶

- `+=` can be used with strings and tuples, even though they’re immutable.
- Creates new objects.

In [14]:

    tuple1 = (10, 20, 30)

In [15]:

    tuple2 = tuple1

In [16]:

    tuple2

Out[16]:

    (10, 20, 30)

In [17]:

    tuple1 += (40, 50)

In [18]:

    tuple1

Out[18]:

    (10, 20, 30, 40, 50)

In [19]:

    tuple2

Out[19]:

    (10, 20, 30)

### Appending Tuples to Lists¶

In [20]:

    numbers = [1, 2, 3, 4, 5]

In [21]:

    numbers += (6, 7)

In [22]:

    numbers

Out[22]:

    [1, 2, 3, 4, 5, 6, 7]

### Tuples May Contain Mutable Objects¶

In [23]:

    student_tuple = ('Amanda', 'Blue', [98, 75, 87])

In [24]:

    student_tuple[2][1] = 85

In [25]:

    student_tuple

Out[25]:

    ('Amanda', 'Blue', [98, 85, 87])

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