If you don’t know what is Unicode, UTF-8 or UTF-16 or if need to refresh your memory on these topics, then before reading this article, check this one What everyone should know about Unicode.
I have divided this article in two parts, one for Python 2 and one for Python 3, since there are some differences in how each handles string and unicode in general. You can either read both of them or read just for the language you are interested in. This article is for Python 3. For Python 2, check out this article.
Python 3 has two built-in types for handling strings. One is the
str type and the other one is
bytes. All the string literals that you normally create in your python program like
str type string literals. These are also the unicode strings. There is no separate
unicode type that we have in Python 2.
Other type is the
bytes type. They are just a series of bytes. To create them, you would have to use
b prefix, like
You would get the type of the string as
bytes. These is the same as the
str type that we have in Python 2. So, in a nutshell, if you are moving from Python 2 to Python 3, you would find that the normal
str type is replaced by
bytes type and the
unicode type is replaced by the
To use unicode characters in Python 3, you have several options-
This would give you a
str type string.
strfunction to convert the
bytesstring into unicode string.
encoding argument specifies the encoding of the input string given as argument to the
str function. Here, I am passing ‘utf8’ as I am using
\xce\xa9 which is the utf-8 encoding for the Ω character.
str function would give decoded unicode string.
bytesdecode function. You can call the decode function on the
bytesstring object and pass in the encoding of the string being called upon to get the unicode string.
Finally to convert the unicode string into
bytes type, use the decode counterpart function encode.
Just pass in the encoding and it will give you the encoded byte string. On my machine it gave the ouput
\xfe\xff is the BOM character followed by the utf-16 encoding of the Ω character
\x03\xa9, but in the reverse order since my machine is a little-endian machine. You may get different result on your machine depending upon your machine endianess.
Now suppose, you want to read in a file which is encoded using UTF-8 or UTF-16. Unlike Python 2, where you have to use the
open function to handle the unicode files, in Python 3, you can use the system’s normal
open function. This function accepts an encoding of the file as an argument and would automatically convert the encoded bytes from the file to the unicode characters for you.
Similary, you can use the
file.write() function to write a unicode string to a file and the function will internally convert your string into the proper series of bytes and write to the disk.
Generally when you have to work with Unicode, what you can do is accept the input from any source, it may be from the user, from a network, from a file, in any encoding, and convert all the data into unicode internally. Then you can safely work on that unicode data, because you know that all the data is in the same format. When the times comes to write or send the data, then convert it back to the original encoding.
Thank you for reading my article. Let me know if you liked my article or any other suggestions for me, in the comments section below. And please, feel free to share :)