4.3 - Working With Tuples

A tuple is a collection of Python objects separated by commas. In some ways, tuples are similar to lists, but they are enclosed in parentheses (...). Tuples can contain a mix of different data types and can be nested.

Tuples are immutable, meaning that once a tuple is created, its values cannot be changed, added, or removed. This immutability makes tuples a safer choice for write-protected data. They support duplicate elements and mixed data types.

4.3.1 - Creating Tuples

Tuples are defined by enclosing elements in parentheses ():

# An empty tuple
empty_tuple = ()

# A tuple with mixed types
mixed_tuple = (1, "hello", 3.14, True)

# A single element tuple (note the comma)
single_element_tuple = (1,)

---

4.3.2 - Accessing Tuple Elements

Tuple elements can be accessed by their index:

my_tuple = (10, 20, 30, 40, 50)

# Accessing the first element
first_element = my_tuple[0]

# Accessing the last element using negative indexing
last_element = my_tuple[-1]

---

4.3.3 - Slicing Tuples

Similar to lists, tuples can be sliced to obtain a subset:

# Getting the first three elements
first_three = my_tuple[:3]

# Getting elements from 2nd to 4th position
slice_middle = my_tuple[1:4]

# Getting the last two elements
last_two = my_tuple[-2:]

---

4.3.4 - Tuple Length

The len() function is used to get the number of elements in a tuple:

length = len(my_tuple)

---

4.3.5 - Checking if an Item Exists in a Tuple

To check if an item exists in a tuple, use the in keyword:

if 20 in my_tuple:
    print("20 is in the tuple")

---

4.3.6 - Iterating Over Tuples

Iterate over the elements of a tuple using a for loop:

for element in my_tuple:
    print(element)

---

4.3.7 - Tuple Concatenation and Repetition

Tuples can be concatenated and repeated using + and * operators:

tuple1 = (1, 2, 3)
tuple2 = (4, 5, 6)

# Concatenation
concatenated = tuple1 + tuple2  # (1, 2, 3, 4, 5, 6)

# Repetition
repeated = tuple1 * 3  # (1, 2, 3, 1, 2, 3, 1, 2, 3)

---

4.3.8 - Tuple Indexing and Counting

• .index(element): Returns the index of the first occurrence of the element.
• .count(element): Returns the count of how many times an element occurs in a tuple.

Example:

print(my_tuple.index(30))  # 2
print(my_tuple.count(20))  # 1

---

4.3.9 - Nested Tuples

Tuples can contain other tuples, forming nested structures:

nested_tuple = (1, (2, 3), (4, 5))

---

4.3.10 - Unpacking Tuples

Tuple unpacking allows assigning each value in the tuple to a variable:

a, b, c = my_tuple[:3]

---

4.3.11 - Immutable Nature of Tuples

Tuples are immutable, meaning their elements cannot be changed after creation. This makes them ideal for fixed data storage.

---

4.3.12 - Converting Lists to Tuples and Vice Versa

• tuple(list): Converts a list to a tuple.
• list(tuple): Converts a tuple to a list.

Example:

my_list = [1, 2, 3]
my_tuple = tuple(my_list)
new_list = list(my_tuple)

---

4.3.13 - Named Tuples (collections.namedtuple)

Named tuples can be used to create tuple-like objects that have fields accessible by attribute lookup as well as being indexable and iterable:

from collections import namedtuple

Point = namedtuple('Point', ['x', 'y'])
pt = Point(1, 2)
print(pt.x, pt.y)  # 1 2

---

4.3.14 - Summary Table of Tuple Methods and Techniques

Method/Technique	Description	Example
Creating Tuples	Define a tuple using parentheses.	my_tuple = (1, 2, 3)
Accessing Elements	Access elements by their index.	element = my_tuple[0]
Slicing Tuples	Get a subset of the tuple.	subset = my_tuple[:2]
len(tuple)	Get the number of elements in the tuple.	length = len(my_tuple)
Checking Item Existence	Check if an item exists in the tuple.	if 2 in my_tuple: ...
Iterating Over Tuples	Iterate over tuple elements using a loop.	for x in my_tuple: print(x)
Tuple Concatenation	Concatenate tuples using +.	concatenated = tuple1 + tuple2
Tuple Repetition	Repeat tuples using *.	repeated = tuple1 * 3
.index(element)	Get the index of the element.	my_tuple.index(3)
.count(element)	Count occurrences of the element.	my_tuple.count(2)
Nested Tuples	Tuples can contain other tuples.	nested = (1, (2, 3))
Unpacking Tuples	Assign each value in the tuple to a variable.	a, b, c = my_tuple
Tuple Immutability	Tuples cannot be changed after creation.
Converting Lists to Tuples	Convert lists to tuples and vice versa.	tuple(my_list), list(my_tuple)
collections.namedtuple	Create tuple-like objects with named fields.	Point = namedtuple('Point', ['x', 'y'])