How to convert a string to utf-8 in Python

Question

I have a browser which sends utf-8 characters to my Python server, but when I retrieve it from the query string, the encoding that Python returns is ASCII. How can I convert the plain string to utf-8?

NOTE: The string passed from the web is already UTF-8 encoded, I just want to make Python to treat it as UTF-8 not ASCII.

Solution 1

In Python 2

>>> plain_string = "Hi!"
>>> unicode_string = u"Hi!"
>>> type(plain_string), type(unicode_string)
(<type 'str'>, <type 'unicode'>)

^ This is the difference between a byte string (plain_string) and a unicode string.

>>> s = "Hello!"
>>> u = unicode(s, "utf-8")

^ Converting to unicode and specifying the encoding.

In Python 3

All strings are unicode. The unicode function does not exist anymore. See answer from @Noumenon

Solution 2

If the methods above don't work, you can also tell Python to ignore portions of a string that it can't convert to utf-8:

stringnamehere.decode('utf-8', 'ignore')

Solution 3

Might be a bit overkill, but when I work with ascii and unicode in same files, repeating decode can be a pain, this is what I use:

def make_unicode(inp):
    if type(inp) != unicode:
        inp =  inp.decode('utf-8')
    return inp

Solution 4

Adding the following line to the top of your .py file:

# -*- coding: utf-8 -*-

allows you to encode strings directly in your script, like this:

utfstr = "ボールト"

Solution 5

If I understand you correctly, you have a utf-8 encoded byte-string in your code.

Converting a byte-string to a unicode string is known as decoding (unicode -> byte-string is encoding).

You do that by using the unicode function or the decode method. Either:

unicodestr = unicode(bytestr, encoding)
unicodestr = unicode(bytestr, "utf-8")

Or:

unicodestr = bytestr.decode(encoding)
unicodestr = bytestr.decode("utf-8")

View more solutions

Comments

[Mudassir]

Try this link http://evanjones.ca/python-utf8.html

[boatcoder]

I think a better title would be How to coerce a string to unicode without translation?

[devssh]

In 2018, python 3 if you get ascii decode error do "some_string".encode('utf-8').decode('utf-8')

[Gopakumar N G]

,I am getting the following error: UnicodeDecodeError: 'utf8' codec can't decode byte 0xb0 in position 2: invalid start byte This is my code: ret=[] for line in csvReader: cline=[] for elm in line: unicodestr = unicode(elm, 'utf-8') cline.append(unicodestr) ret.append(cline)

[jfs]

It is not what OP asks. But avoid such string literals anyway. It creates Unicode string in Python 3 (good) but it is a bytestring in Python 2 (bad). Either add from __future__ import unicode_literals at the top or use u'' prefix. Don't use non-ascii characters in bytes literals. To get utf-8 bytes, you could utf8bytes = unicode_text.encode('utf-8') later if it is necessary.

[Noumenon]

None of this applies in Python 3, all strings are unicode and unicode() doesn't exist.

[智障的人]

Kind of bumping this, but thanks. This fixed an issue where I was trying to print unicode and was getting �s.

[Tanguy]

How to you convert u back to a str format (convert u back to s)?

[Haroldo_OK]

This code will only work as long as the text does not contain non-ascii characters; a simple accented character on the string will make it fail.

[saran3h]

Got AttributeError: 'str' object has no attribute 'decode'

[duhaime]

@saran3h it sounds like you're using Python 3, in which case Python should handle encoding issues for you. Have you tried reading your document without specifying an encoding?

[Ortal Turgeman]

@jfs how will from __future__ import unicode_literals help me to convert a string with non-ascii characters to utf-8?

[jfs]

@OrtalTurgeman I'm not answering the question. Look, it is a comment, not an answer. My comment addresses the issue with the code in the answer. It tries to create a bytestring with non-ascii characters on Python 2 (it is a SyntaxError on Python 3 — bytes literals forbid that).

[Sha2b]

Hi, if you have "2340" in a string variable, and you want to print the unicode character U+2340 (⍀), is there any way to do that?

[Vishesh Mangla]

Python by default picks system encoding. In windows 10 it's cp1252 which is different from utf-8. I wasted few hours on it while using codecs.open() in py 3.8

[Gino Mempin]

What is unidecode? Is it this pypi.org/project/Unidecode? Please provide info if it's a 3rd-party package, and how to install/use it.

[U12-Forward]

@Sha2b chr(0x2340) gives: ⍀

[Mike Pennington]

This no longer works, as written... the unicode type doesn't exist in python3