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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