# 5 Best Ways to Check Whether the Average Character of the String is Present in Python

π‘ Problem Formulation: In Python, determining if the average character (based on ASCII value) of a string exists within the string itself can be a unique problem to solve. For instance, given the string “abcde”, the average character would be ‘c’. This article explores five different methods to check whether this average character is indeed a part of the original string.

## Method 1: Using ASCII Values and the `chr()` Function

This method revolves around calculating the average ASCII value of all characters in the string and then converting this average back into a character using the `chr()` function. The presence of this character in the original string is then checked.

Here’s an example:

```def average_char_present(s):
avg_ascii = int(round(sum(map(ord, s)) / len(s)))
avg_char = chr(avg_ascii)
return avg_char in s

string = "abcde"
print(average_char_present(string))```

Output:

`True`

This snippet defines a function `average_char_present` that first calculates the average of the ASCII values of the characters in the string, rounds it to the nearest whole number, converts that average ASCII value to a character, and finally checks if this character is present in the original string.

## Method 2: Using the `statistics` Module

The `statistics` Python module includes a `mean()` function that can be used to find the average of a list of numbers. We use it to compute the average of the ASCII values and check for the character’s presence as done in the first method.

Here’s an example:

```import statistics

def average_char_present(s):
avg_ascii = round(statistics.mean(map(ord, s)))
avg_char = chr(avg_ascii)
return avg_char in s

string = "hello"
print(average_char_present(string))```

Output:

`False`

In this code, the `average_char_present` function is defined using the `statistics.mean()` function to compute the average ASCII value, followed by similar steps of converting it to a character and checking if it’s in the string as outlined in Method 1.

## Method 3: Using List Comprehension and the `in` Operator

This method simplifies the process by using a list comprehension to calculate the sum and subsequently the average character, combining the steps into a one-liner within the return statement.

Here’s an example:

```def average_char_present(s):
return chr(round(sum([ord(char) for char in s]) / len(s))) in s

string = "world"
print(average_char_present(string))```

Output:

`True`

The function `average_char_present` here makes use of list comprehension within the `sum()` call to calculate the average ASCII value and immediately checks for the character’s presence in the string, thus succinctly accomplishing the task.

## Method 4: Using the `reduce()` Function from `functools`

The `reduce()` function from `functools` can be used to accumulate the ASCII values, computing the average character in a functional programming style. This method is more efficient for longer strings.

Here’s an example:

```from functools import reduce

def average_char_present(s):
avg_ascii = round(reduce(lambda x, y: x + y, map(ord, s)) / len(s))
avg_char = chr(avg_ascii)
return avg_char in s

string = "function"
print(average_char_present(string))```

Output:

`True`

The code defines `average_char_present` using `reduce()` to sum the ASCII values, then calculates the average and checks for the character’s presence. This approach may be preferred for its functional programming style and efficiency with long strings.

## Bonus One-Liner Method 5: Using a Lambda and the `all()` Function

A compact one-liner method can be achieved by using a lambda function inside the `all()` function to evaluate the average character presence directly in the return statement.

Here’s an example:

```string = "syntax"
print((lambda s: chr(round(sum(map(ord, s)) / len(s))) in s)(string))```

Output:

`False`

This one-liner lambda function directly calculates the sum, finds the average ASCII value, converts it to a character, and checks its presence in the original string. This method is concise but may sacrifice readability for brevity.

## Summary/Discussion

• Method 1: ASCII Values and `chr()`. Strengths: Straightforward and easy to understand. Weaknesses: Requires manual implementation of the average calculation.
• Method 2: Using `statistics` Module. Strengths: Utilizes built-in functions for cleaner code. Weaknesses: Overhead of importing an additional module.
• Method 3: List Comprehension. Strengths: More Pythonic with concise syntax. Weaknesses: Might be less readable to beginners.
• Method 4: `reduce()` Function. Strengths: Efficient and functional programming approach. Weaknesses: Can be less intuitive than other methods.
• Method 5: Lambda One-Liner. Strengths: Extremely concise. Weaknesses: Readability can suffer, making it hard to debug or maintain.