Code Golf in Python

Code golfing is a programming competition that challenges participants to write a program that solves a specific problem in as few characters as possible. In other words, code golfing is all about writing clean code. While code golfing can be done in any programming language, Python is particularly suited to this challenge due to its concise syntax and powerful built-in functions.

In this article, we will explore some tips and strategies for code golf in Python, while providing applicable examples and output.

Use list comprehension

List comprehensions are a powerful tool in Python for creating lists in a concise and readable way. In code golf, list comprehensions can replace longer loops and conditional statements. For example, consider the following code, which creates a list containing all even numbers between 1 and 10:

even_numbers = []
for i in range(1, 11):
    if i % 2 == 0:
        even_numbers.append(i)

This code can be reduced to one line using list comprehension:

The Chinese translation of

Example

is:

Example

even_numbers = [i for i in range(1, 11) if i % 2 == 0]
print(even_numbers)

Output

[2, 4, 6, 8, 10]

This code uses list comprehensions instead of a for loop and the append() method to generate the same list of even numbers between 1 and 10 as the previous example. Using list comprehensions can significantly reduce the amount of code required to achieve a result, making them a powerful tool in code golf.

Use built-in functions

Python has a wide range of built-in functions that can perform common operations in a concise way. When playing code golf, it's important to become familiar with these functions and their syntax. For example, consider the following code, which calculates the sum of all even numbers between 1 and 10:

even_numbers = [i for i in range(1, 11) if i % 2 == 0]
even_sum = 0
for num in even_numbers:
    even_sum += num

Using the built-in sum() function, this code can be compressed into one line:

The Chinese translation of

Example

is:

Example

even_sum = sum([i for i in range(1, 11) if i % 2 == 0])
print(even_sum)

Output

30

It takes less code to generate a list of even numbers from 1 to 10 using sum() and list comprehensions, and prints their sum as output.

Use shortcuts

In Python, there are some shortcuts and abbreviations that can effectively reduce the amount of code required for certain operations. For example, let's look at the following code, which verifies whether a specific value exists in a list:

a, b = 0, 1
for i in range(10):
    print(a)
    a, b = b, a+b

This code can be compressed into one line using the lambda function and the reduce() function in the functools module:

The Chinese translation of

Example

is:

Example

from functools import reduce
print(*(reduce(lambda f, _: f+[f[-1]+f[-2]], range(8), [0, 1])), sep='\n')

Output

3
0
1
1
2
3
5
8
13

This program uses the reduce() and lambda functions to count the number of vowels in "Hello, World!", generates the first 8 Fibonacci numbers, and then prints out the sequence.

Use Lambda function

In Python, the lambda function is an unnamed function that can be declared in one line of code. Lambda functions are particularly useful for code compression, when you need to quickly define a simple function. For example, consider the following code, which sorts a list of tuples based on the second element of each tuple:

my_list = [(1, 3), (2, 1), (3, 2)]
def sort_by_second(elem):
    return elem[1]
sorted_list = sorted(my_list, key=sort_by_second)

Use the lambda function to compress this code into one line:

The Chinese translation of

Example

is:

Example

my_list = [(1, 3), (2, 1), (3, 2)]
sorted_list = sorted(my_list, key=lambda x: x[1])

Output

[(2, 1), (3, 2), (1, 3)]

By using lambda functions, we can define sorting criteria in a concise and readable way without having to define a separate function.

Avoid redundant code

When playing code golf, it is important to avoid writing redundant or repetitive code. This may include unnecessary variables, loops, or conditional statements. For example, consider the following code that counts the number of vowels in a string:

my_string = "Hello, World!"
vowel_count = 0
for char in my_string:
    if char in "aeiouAEIOU":
        vowel_count += 1
print(vowel_count)

Using the count() function and str.lower() method, this code can be compressed into one line:

The Chinese translation of

Example

is:

Example

my_string = "Hello, World!"
print(sum(my_string.lower().count(vowel) for vowel in "aeiou"))

Output

3

By using the count() function and str.lower() method, we can perform the same operation in a more concise and readable way.

The Chinese translation of

Code Golfing Examples

is:

Code Golfing Examples

To demonstrate some of the techniques and strategies we’ve discussed, let’s look at some Python code golf examples.

Example: FizzBuzz

The FizzBuzz problem is a common coding challenge that involves printing numbers from 1 to 100, replacing multiples of 3 with "Fizz", multiples of 5 with "Buzz", and replacing multiples of 3 with "Buzz" that are both multiples of 3 and 5. Multiple numbers are replaced with "FizzBuzz". Here's a solution to the FizzBuzz problem using traditional loops and conditional methods:

for i in range(1, 101):
    if i % 15 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)

Using list comprehension and string concatenation, this code can be compressed into one line:

print('\n'.join("Fizz"*(i%3==0)+"Buzz"*(i%5==0) or str(i) for i in range(1,101)))

By using list comprehensions and string concatenation, we can significantly reduce the amount of code required to solve FizzBuzz problems.

The output program replaces multiples of 3 with "Fizz", multiples of 5 with "Buzz", and numbers that are both multiples of 3 and 5 with "FizzBuzz". All other numbers are printed as is.

in conclusion

In summary, code golf is a popular programming method that involves writing code with as few characters as possible to accomplish a task. In Python, there are several techniques you can use to reduce code size, such as using list comprehensions, lambda functions, and built-in functions like sum() and sorted(). While code golf can be a fun and educational exercise, the readability and maintainability of your code should always be your top priority when writing code for real-world applications. So while it may be tempting to pursue the shortest possible code, it's important for yourself and others to keep your code clear and understandable.

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