How to Turn a Letter Into a Number in Python

In the world of programming, you often have to convert data from one type to another. One common conversion you might need to make is turning a letter into a number.

In Python, this is surprisingly easy to do, thanks to the ASCII (American Standard Code for Information Interchange) standard, which assigns a unique numeric code to each letter and special character. This tutorial will guide you step-by-step on how to achieve this conversion.

Step 1: Understand ASCII

The ASCII standard assigns integer values between 0 and 127 for each character. For instance, the uppercase letter ‘A’ has an ASCII value of 65. On the other hand, the lowercase ‘a’ has a value of 97. Knowing this allows you to convert letters to numbers in Python. For a full ASCII table, you can visit this page.

Step 2: Use the ord() Function

To convert a letter to a number, you can use the built-in Python function ord(). This function takes a single character as an argument and returns its ASCII value.

For example:

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letter = 'A'
number = ord(letter)
print(number)

The number 65 would be printed to the console because the ASCII value of ‘A’ is 65.

65

Step 3: Convert a String of Characters

If you have a string of characters you want to convert, you can apply the ord() function iteratively. By using a loop, a list comprehension, or a map function, you can convert each character to its numerical value.

Here is how to do it with a for loop:

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string = "Hello"
numbers = []
for char in string:
  numbers.append(ord(char))
print(numbers)

And this is the output:

[72, 101, 108, 108, 111]

Full Code

Here is the complete code that was used in this tutorial:

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letter = 'A'
number = ord(letter)
print(number)
 
string = "Hello"
numbers = []
for char in string:
  numbers.append(ord(char))
print(numbers)

Conclusion

Turning a letter into a number in Python is straightforward, thanks to the ASCII standard and the flexible built-in functions Python offers. Whether you need to convert individual characters or entire strings, you now have the tools you need to accomplish the task efficiently.