Python Cookbook

Converting Between Characters and Values

Credit: Luther Blissett

Problem

You need to turn a character into its numeric ASCII (ISO) or Unicode code, and vice versa.

Solution

That’s what the built-in functions ord and chr are for:

>>> print ord('a')
97
>>> print chr(97)
a

The built-in function ord also accepts as an argument a Unicode string of length one, in which case it returns a Unicode code, up to 65536. To make a Unicode string of length one from a numeric Unicode code, use the built-in function unichr:

>>> print ord(u'u2020')
8224
>>> print unichr(8224)
u' '

Discussion

It’s a mundane task, to be sure, but it is sometimes useful to turn a character (which in Python just means a string of length one) into its ASCII (ISO) or Unicode code, and vice versa. The built-in functions ord, chr, and unichr cover all the related needs. Of course, they’re quite suitable with the built-in function map:

>>> print map(ord, 'ciao')
[99, 105, 97, 111]

To build a string from a list of character codes, you must use both map and ''.join:

>>> print ''.join(map(chr, range(97, 100)))
abc

See Also

Documentation for the built-in functions chr, ord, and unichr in the Library Reference.