How to convert a string to utf-8 in Python

问题:

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.

回答1:

>>> 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.

回答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')

回答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(input):
    if type(input) != unicode:
        input =  input.decode('utf-8')
        return input
    else:
        return input

回答4:

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")

回答5:

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"

回答6:

city = 'Ribeir\xc3\xa3o Preto'
print city.decode('cp1252').encode('utf-8')

回答7:

In Python 3.6, they do not have a built-in unicode() function. To convert a string to unicode, simply get the unicode value of the character, and do this:

my_str = "\u221a25"
my_str = u"{}".format(my_str)
print(my_str)
>>> √25

回答8:

Translate with ord() and unichar(). Every unicode char have a number asociated, something like an index. So Python have a few methods to translate between a char and his number. Downside is a ñ example. Hope it can help.

>>> C = 'ñ'
>>> U = C.decode('utf8')
>>> U
u'\xf1'
>>> ord(U)
241
>>> unichr(241)
u'\xf1'
>>> print unichr(241).encode('utf8')
ñ