Convert Unicode code point and character to each other (chr, ord) | note.nkmk.me (2024)

In Python, the built-in functions chr() and ord() are used to convert between Unicode code points and characters.

• Built-in Functions - chr() — Python 3.9.7 documentation
• Built-in Functions - ord() — Python 3.9.7 documentation

A character can also be represented by writing a hexadecimal Unicode code point with \x, \u, or \U in a string literal.

• Unicode HOWTO - Python’s Unicode Support — Python 3.9.7 documentation

This article describes the following contents.

• Convert character to Unicode code point: ord()
• Convert Unicode code point to character: chr()
• Use Unicode code points in strings: \x, \u, \U

Convert character to Unicode code point: ord()

By specifying a string of one character as an argument of ord(), the Unicode code point of the character is returned as an integer int.

i = ord('A')print(i)# 65print(type(i))# <class 'int'>

An error occurs if you specify a string of more than two characters.

# ord('abc')# TypeError: ord() expected a character, but string of length 3 found

Unicode code points are often written in hexadecimal notation. Use the built-in function hex() to convert an integer to a hexadecimal string.

s = hex(i)print(s)# 0x41print(type(s))# <class 'str'>

The built-in format() function can be used to specify more detailed formatting, such as zero-filling and the prefix 0x.

• Format strings and numbers with format() in Python

print(format(i, '04x'))# 0041print(format(i, '#06x'))# 0x0041

In summary, the hexadecimal Unicode code point for a particular character can be obtained as follows.

print(format(ord('X'), '#08x'))# 0x000058print(format(ord('💯'), '#08x'))# 0x01f4af

Flags and other emoji are represented by multiple Unicode code points.

• https://unicode.org/Public/emoji/4.0/emoji-sequences.txt

Note that as of Python 3.7.3, ord() does not support such emoji and an error raises. If you check the number of characters of those emoji with the built-in function len(), the number of Unicode code points is returned.

# ord('🇯🇵')# TypeError: ord() expected a character, but string of length 2 foundprint(len('🇯🇵'))# 2

Convert Unicode code point to character: chr()

chr() returns the string str representing a character whose Unicode code point is the specified integer int.

print(chr(65))# Aprint(type(chr(65)))# <class 'str'>

In Python, an integer can be written in hexadecimal with 0x, so you can specify it as an argument of chr(). It doesn't matter if it is filled with zeros.

print(65 == 0x41)# Trueprint(chr(0x41))# Aprint(chr(0x000041))# A

If you want to convert a hexadecimal string representing a Unicode code point to a character, convert the string to an integer and then pass it to chr().

Use int() to convert a hexadecimal string into an integer. Specify the radix 16 as the second argument.

s = '0x0041'print(int(s, 16))# 65print(chr(int(s, 16)))# A

The second argument can be 0 if the string is prefixed with 0x. See the following article for more details on the handling of hexadecimal numbers and strings.

• Convert binary, octal, decimal, and hexadecimal in Python

Unicode code points are often written in the form of U+XXXX. To convert such a string to a character of that code point, just select the numeric part of the string with the slice.

• How to slice a list, string, tuple in Python

s = 'U+0041'print(s[2:])# 0041print(chr(int(s[2:], 16)))# A

Use Unicode code points in strings: \x, \u, \U

If you write \x, \u, or \U and a hexadecimal Unicode code point in a string literal, it is treated as that character.

It should be 2, 4, or 8 digits like \xXX, \uXXXX, and \UXXXXXX, respectively. An error is raised if the number of digits is not correct.

print('\x41')# Aprint('\u0041')# Aprint('\U00000041')# Aprint('\U0001f4af')# 💯# print('\u041')# SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 0-4: truncated \uXXXX escape# print('\U0000041')# SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 0-8: truncated \UXXXXXXXX escape

Each code is treated as one character. You can check it with the built-in function len() which returns the number of characters.

print('\u0041\u0042\u0043')# ABCprint(len('\u0041\u0042\u0043'))# 3

Note that in raw strings where escape sequences are disabled, the string is treated as is.

• Raw strings in Python

print(r'\u0041\u0042\u0043')# \u0041\u0042\u0043print(len(r'\u0041\u0042\u0043'))# 18