Day 16: Python List Comprehension

Creating Lists with List Comprehension

List comprehensions in Python offer a succinct method to create lists. They enable you to define the elements of a list using a single line of code.

# Create a list of the squares of the numbers from 1 to 10 using list comprehension
numbers = [x**2 for x in range(1, 11)]
print(numbers)  
# Output: [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Modifying Lists with List Comprehension

List comprehensions can also be used to modify the elements of a list. For example, you can create a list of uppercase versions of the words in a list.

# Create a list of the uppercase versions of the words in a list using list comprehension
words = ["apple", "banana", "cherry"]
uppercase_words = [word.upper() for word in words]
print(uppercase_words)  
# Output: ["APPLE", "BANANA", "CHERRY"]

Filtering Lists with List Comprehension

The 'if' clause can be utilized to filter the items included in the list.

# Use an 'if' clause in list comprehension to filter words that start with 'a'
words = ["apple", "banana", "cherry", "apricot"]
a_words = [word for word in words if word[0] == "a"]
print(a_words)  
# Output: ["apple", "apricot"]

Altering List Elements with List Comprehension

You can also use list comprehensions to alter the elements of a list. For example, you can double the value of each number in the list or increment the value of each number in the list by one.

# Use list comprehension to double the value of each number in the list
numbers = [1, 2, 3, 4, 5]
numbers = [x * 2 for x in numbers]
print(numbers)  
# Output: [2, 4, 6, 8, 10]

# Use list comprehension to add 1 to the value of each number in the list
numbers = [x + 1 for x in numbers]
print(numbers)  
# Output: [3, 5, 7, 9, 11]

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