Python Ord and Chr Functions: Working with Unicode

In this tutorial, you’ll learn how to use the Python ord and chr functions to allow you to work better with Unicode. The Unicode standard has replaced many confusing encodings and is used to represent each character (including emojis) with a number.

The Python ord() function converts a character into an integer that represents the Unicode code of the character. Similarly, the chr() function converts a Unicode code character into the corresponding string.

You’ll learn a quick refresher on Unicode and how string characters can be represented in different ways in Python. Then, you’ll learn how the chr() and ord() functions work in Python, both for single characters and for multiple characters.

What is Unicode and How is it Used in Python?

Before diving into the ord and chr functions, let’s start off by covering why learning about Unicode is so important. At a basic level, computers work with numbers – because of this, the characters and letters that appear on a screen are numbers under the hood.

In the past, many different types of encoding existed. However, many of these were incomplete when considering the vast variety of characters that exist on the internet. In order to resolve this, the Unicode Consortium standardized specifications of how to represent characters in 1991.

The Unicode standard assigned numerical values to every type of character, from letters to symbols to emojis. The standard allowed computers to have a much easier time understanding symbols, especially as more and more symbols are being added to the internet.

The image below shows how a string character can be converted to its numeric, Unicode representation. This even includes emojis! The Unicode standard includes values for Unicode numbers ranging from 0 through 1,114,111.

Python ord() Function: Unicode to Integer

Let’s see what this looks like:

# Converting Unicode to Int Using ord()
character = 'd'
print(ord(character))

# Returns: 100

We can see the integer representation of the Unicode letter 'd' is 100. The function ord() works by taking a single character as its input, the character that you want to convert to an integer.

Passing Multiple Characters into the Python ord() Function

The Python ord() function allows you to only pass in a single character. Let’s see what happens when we pass in more than one character:

# Converting Unicode to Int Using ord()
character = 'datagy'
print(ord(character))

# Raises: TypeError: ord() expected a character, but string of length 6 found

We can see that passing in more than one character into the ord() function raises a TypeError. This happens because the function expects only a single character to be passed in.

Using the Python ord() for Multiple Characters

In order to resolve the TypeError that is raised when more than one character is passed into the ord() function, we need to iterate over each character in the string. Because Python strings are iterable objects, we can directly iterate over these string values.

Let’s see how we can repeat our earlier example without raising a TypeError:

# Converting Multiple Characters into Integers
word = 'datagy'
unicode = []
for letter in word:
    unicode.append(ord(letter))

print(unicode)

# Returns:
# [100, 97, 116, 97, 103, 121]

We can now see the integer representation of our Unicode string. This was accomplished by looping over each letter in the string and applying the ord() function to it.

In the next section, you’ll learn about the reverse of this function: the chr() function, which allows you to pass in a Unicode number and return a string representation.

Python chr() Function: Integer to Unicode Character

The Python chr function does the opposite of the ord function, returning a Unicode character when an integer value is passed in.

Let’s convert an integer value into its Unicode counterpart:

# Convert an Integer into a Unicode String
number = 100
unicode = chr(number)

print(unicode)

# Returns: d

We can see that by passing in an integer, a string character is returned.

Converting Multiple Integers to Strings Using Python chr()

Let’s try to convert some values from integers into their Unicode counterparts:

# Converting Integers to their Unicode Equivalent
numbers = [100, 97, 116, 97, 103, 121]

for number in numbers:
    print(chr(number))

# Returns:
# d
# a
# t
# a
# g
# y

We can go further and convert this list of numbers into an actual Python string. We can do this by using the .join() method. Let’s take a look at how this works. Rather than using a for loop, let’s use a Python list comprehension to simplify this process:

# Converting Integers to their Unicode Equivalent
numbers = [100, 97, 116, 97, 103, 121]
word = ''.join([chr(number) for number in numbers])

print(word)

# Returns: datagy

In the example above, we used the "".join() method to convert our resulting list of strings to a single string.

As of the writing of this article, the function accepts any value between 0 and 1,114,111, representing all the available Unicode characters. If a value outside of this range is passed into the function, the function will raise a ValueError. Let’s see what this looks like:

# Raising a ValueError with chr
chr(1114112)

# Raises: ValueError: chr() arg not in range(0x110000)

We can see that, as expected, a ValueError was raised.

Working with Hexadecimal Data in Python Ord and Chr

In Python, Hexadecimal numbers are numbers represented in other common bases. The hexadecimal format changes the base to 16 and can be used with both the chr and ord functions. In Python, these numbers can be used by prefixing the integer with 0x.

We can convert an integer into its hexadecimal equivalent by using the hex function. Let’s give this a shot:

# Converting an Integer to a Hexadecimal Number
number = 100
hex_number = hex(100)

print(hex_number)

# Returns: 0x64

Now that we have the hexadecimal value for the number 100, we can pass this into the chr function to convert it to its Unicode representation:

# Converting Hexadecimal to Unicode
print(chr(0x64))

# Returns: d

Here we can see that the 0x64 is a valid number representation in Python. Python will interpret the 0x prefix to represent hexadecimal formats and will convert the value into its Unicode representation.

Conclusion

In this tutorial, you learned how to work with the chr and ord functions in Python. These functions allow you to translate unicode to string characters and string characters to unicode. You also learned how to use the ord() function for multiple characters. Finally, you learned how to work with hexadecimal data in Python, when using the chr and ord functions.

To learn more about the Python ord and chr functions, check out the official documentation here.

Additional Resources

To learn more about related topics, check out these tutorials:

• Python: Remove Special Characters from a String
• Python: Remove the First N Characters from a String
• Python: Remove Newline Character from String