Definition of Tuples
- Tuples are used to store multiple items in a single variable.
- One of the four built-in data types in Python to store collections of data: List, Tuple, Set, and Dictionary.
- Tuples are ordered and unchangeable collections.
- Written with round brackets
( ).
-
Tuple Example
mytuple = ("apple", "banana", "cherry") print(mytuple) -
Tuple Properties
- Ordered: Items have a defined order that does not change.
- Unchangeable: Items cannot be modified, added, or removed once the tuple is created.
- Allows Duplicates: Tuples can contain duplicate values.
-
Tuple Indexing
- Tuple items are indexed starting from
[0]for the first item,[1]for the second, and so on.
- Tuple items are indexed starting from
-
Example of Duplicate Values
thistuple = ("apple", "banana", "cherry", "apple", "cherry") print(thistuple) -
Tuple Length
- Use the
len()function to determine the number of items in a tuple.
Example:
thistuple = ("apple", "banana", "cherry") print(len(thistuple)) - Use the
-
Tuple With One Item
- To create a single-item tuple, include a trailing comma:
thistuple = ("apple",) # Tuple print(type(thistuple)) thistuple = ("apple") # Not a tuple print(type(thistuple)) -
Tuple Items - Data Types
- Items in a tuple can be of any data type. Examples:
- Strings:
tuple1 = ("apple", "banana", "cherry") - Integers:
tuple2 = (1, 5, 7, 9, 3) - Booleans:
tuple3 = (True, False, False)
- Strings:
- A tuple can also mix different data types:
tuple1 = ("abc", 34, True, 40, "male")
- Items in a tuple can be of any data type. Examples:
-
Tuple Data Type
- Tuples are objects of the data type
<class 'tuple'>. Example:
mytuple = ("apple", "banana", "cherry") print(type(mytuple)) - Tuples are objects of the data type
-
The
tuple()Constructor- Tuples can also be created using the
tuple()constructor. Example:
thistuple = tuple(("apple", "banana", "cherry")) # Double round brackets print(thistuple) - Tuples can also be created using the
-
Python Collections Overview
- List: Ordered, changeable, allows duplicates.
- Tuple: Ordered, unchangeable, allows duplicates.
- Set: Unordered, unindexed, no duplicates, items are unchangeable (but can be added/removed).
- Dictionary: Ordered (from Python 3.7 onwards), changeable, no duplicate keys.
-
Choosing a Collection Type
- Understanding the properties of collection types is essential for efficiency, meaning retention, and security.
-
Exercise Example
- Identify the tuple:
thistuple = ('apple', 'banana', 'cherry') # Tuple thistuple = ['apple', 'banana', 'cherry'] # List thistuple = {'apple', 'banana', 'cherry'} # Set
Accessing Tuple Items by Index
- Use square brackets
[ ]to access tuple items by their index. - Example:
thistuple = ("apple", "banana", "cherry") print(thistuple[1]) # Output: banana - Note: The first item has index
0.
- Use square brackets
Negative Indexing
- Negative indexing starts from the end of the tuple.
-1refers to the last item,-2refers to the second last item, and so on.- Example:
thistuple = ("apple", "banana", "cherry") print(thistuple[-1]) # Output: cherry
Range of Indexes
- Specify a range of indexes to retrieve multiple items.
- The result is a new tuple with the specified items.
- Example:
thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango") print(thistuple[2:5]) # Output: ('cherry', 'orange', 'kiwi') - Note: The range includes the start index but excludes the end index.
Leaving Out Start Value
- Leaving out the start index begins the range from the first item.
- Example:
thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango") print(thistuple[:4]) # Output: ('apple', 'banana', 'cherry', 'orange')
Leaving Out End Value
- Leaving out the end index continues the range to the last item.
- Example:
thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango") print(thistuple[2:]) # Output: ('cherry', 'orange', 'kiwi', 'melon', 'mango')
Range of Negative Indexes
- Use negative indexes to specify a range starting from the end.
- Example:
thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango") print(thistuple[-4:-1]) # Output: ('orange', 'kiwi', 'melon')
Check if an Item Exists
- Use the
inkeyword to check if a specific item exists in a tuple. - Example:
thistuple = ("apple", "banana", "cherry") if "apple" in thistuple: print("Yes, 'apple' is in the fruits tuple")
- Use the
Exercise Question
- What is the index number of the first item?
Answer:0.
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- What is the index number of the first item?
Here are all the key points summarized from the provided text about updating tuples in Python:
1. Tuples Are Unchangeable (Immutable)
- Tuples are immutable, meaning you cannot change, add, or remove items once created.
- However, workarounds exist.
2. Change Tuple Values
- Tuples themselves cannot be directly modified, but you can:
- Convert the tuple into a list.
- Modify the list.
- Convert the list back into a tuple.
Example:
x = ("apple", "banana", "cherry")
y = list(x)
y[1] = "kiwi"
x = tuple(y)
print(x) # Output: ('apple', 'kiwi', 'cherry')
3. Add Items to a Tuple
-
Tuples do not have an
append()method, but you can add items using two approaches:(1) Convert into a List:
- Convert the tuple into a list, add the new item(s), and convert it back into a tuple.
Example:thistuple = ("apple", "banana", "cherry") y = list(thistuple) y.append("orange") thistuple = tuple(y) print(thistuple) # Output: ('apple', 'banana', 'cherry', 'orange')
(2) Add Tuple to Tuple:
- Create a new tuple with the additional item(s) and concatenate it to the existing tuple.
Example:thistuple = ("apple", "banana", "cherry") y = ("orange",) thistuple += y print(thistuple) # Output: ('apple', 'banana', 'cherry', 'orange')
Note: When creating a tuple with one item, always include a comma (
,) after the item to identify it as a tuple. - Convert the tuple into a list, add the new item(s), and convert it back into a tuple.
4. Remove Items from a Tuple
- Direct removal is not possible because tuples are immutable.
- Workaround: Convert the tuple into a list, remove the item(s), and convert it back into a tuple.
Example:
thistuple = ("apple", "banana", "cherry")
y = list(thistuple)
y.remove("apple")
thistuple = tuple(y)
print(thistuple) # Output: ('banana', 'cherry')
- Delete the Entire Tuple:
- Use the
delkeyword to delete the entire tuple.
Example:thistuple = ("apple", "banana", "cherry") del thistuple # print(thistuple) will raise an error because the tuple no longer exists
- Use the
5. Exercise Question
You cannot change the items of a tuple, but there are workarounds. Which of the following suggestions will work?
- Correct Answer:
- Convert tuple into a list, change item, convert back into a tuple.
- Incorrect Answers:
- Convert tuple into a set, change item, convert back into a tuple.
- Convert tuple into a dictionary, change item, convert back into a tuple.
----
Here are all the key points summarized from the provided text about unpacking tuples in Python:
1. Packing a Tuple
- Packing refers to assigning multiple values to a tuple.
Example:
fruits = ("apple", "banana", "cherry")
2. Unpacking a Tuple
- Unpacking is extracting the values from a tuple into individual variables.
- The number of variables must match the number of items in the tuple, unless an asterisk is used.
Example:
fruits = ("apple", "banana", "cherry")
(green, yellow, red) = fruits
print(green) # Output: apple
print(yellow) # Output: banana
print(red) # Output: cherry
3. Using Asterisk (*)
- If the number of variables is less than the number of tuple items, an asterisk (
*) can be used to collect the remaining values into a list.
Example 1: Assign the remaining values to the last variable:
fruits = ("apple", "banana", "cherry", "strawberry", "raspberry")
(green, yellow, *red) = fruits
print(green) # Output: apple
print(yellow) # Output: banana
print(red) # Output: ['cherry', 'strawberry', 'raspberry']
Example 2: Assign the remaining values to a middle variable:
- The asterisk can be added to a variable that is not the last one. Python will adjust values to fit the remaining variables.
fruits = ("apple", "mango", "papaya", "pineapple", "cherry")
(green, *tropic, red) = fruits
print(green) # Output: apple
print(tropic) # Output: ['mango', 'papaya', 'pineapple']
print(red) # Output: cherry
4. Exercise Question
Consider the following code:
fruits = ('apple', 'banana', 'cherry')
(x, y, z) = fruits
print(y)
What will be the value of y?
- Correct Answer:
banana
--------------------------
Here are all the key points about looping through tuples in Python:
1. Loop Through a Tuple Using a for Loop
- You can directly iterate through tuple items using a
forloop. Example:
thistuple = ("apple", "banana", "cherry")
for x in thistuple:
print(x)
2. Loop Through a Tuple Using Index Numbers
- You can iterate through a tuple by referring to its index numbers.
- Use the
range()andlen()functions to create an iterable sequence of index numbers. Example:
thistuple = ("apple", "banana", "cherry")
for i in range(len(thistuple)):
print(thistuple[i])
3. Loop Through a Tuple Using a while Loop
- A
whileloop can also be used to iterate through a tuple. - Use the
len()function to determine the length of the tuple. - Start at index
0and increase the index by1after each iteration. Example:
thistuple = ("apple", "banana", "cherry")
i = 0
while i < len(thistuple):
print(thistuple[i])
i += 1
4. Exercise Question
What is the correct syntax for looping through the items of a tuple?
Options:
-
for x in ('apple', 'banana', 'cherry'): print(x) -
for x in ('apple', 'banana', 'cherry') print(x) -
foreach x in ('apple', 'banana', 'cherry') print(x)
Correct Answer:
Option 1
for x in ('apple', 'banana', 'cherry'):
print(x)
---------------------Here are the key points about joining and multiplying tuples in Python:
1. Join Two Tuples Using the + Operator
- You can join two or more tuples by using the
+ operator.
Example:
tuple1 = ("a", "b", "c")
tuple2 = (1, 2, 3)
tuple3 = tuple1 + tuple2
print(tuple3) # Output: ('a', 'b', 'c', 1, 2, 3)
2. Multiply Tuples Using the * Operator
- You can multiply a tuple to repeat its content a specific number of times using the
* operator.
Example:
fruits = ("apple", "banana", "cherry")
mytuple = fruits * 2
print(mytuple) # Output: ('apple', 'banana', 'cherry', 'apple', 'banana', 'cherry')
3. Exercise Question
What is the correct syntax for joining tuple1 and tuple2 into tuple3?
Options:
tuple3 = join(tuple1, tuple2)tuple3 = tuple1 + tuple2tuple3 = [tuple1, tuple2]
Correct Answer:
Option 2
tuple3 = tuple1 + tuple2
----------------------------------
Python - Tuple Methods
Python provides two built-in methods for working with tuples:
1. count() Method
- Description: Returns the number of times a specified value occurs in the tuple.
- Example:
thistuple = (1, 2, 3, 2, 2, 4)
occurrences = thistuple.count(2)
print(occurrences) # Output: 3
2. index() Method
- Description: Searches the tuple for a specified value and returns the position (index) of its first occurrence.
- Example:
thistuple = (1, 2, 3, 4, 5)
position = thistuple.index(3)
print(position) # Output: 2
These methods can be applied directly to any tuple to analyze or retrieve specific data.
