Write to UTF-8 file in Python

Question

I'm really confused with the codecs.open function. When I do:

file = codecs.open("temp", "w", "utf-8")
file.write(codecs.BOM_UTF8)
file.close()

It gives me the error

UnicodeDecodeError: 'ascii' codec can't decode byte 0xef in position 0: ordinal not in range(128)

If I do:

file = open("temp", "w")
file.write(codecs.BOM_UTF8)
file.close()

It works fine.

Question is why does the first method fail? And how do I insert the bom?

If the second method is the correct way of doing it, what the point of using codecs.open(filename, "w", "utf-8")?

Answer 1

I believe the problem is that codecs.BOM_UTF8 is a byte string, not a Unicode string. I suspect the file handler is trying to guess what you really mean based on "I'm meant to be writing Unicode as UTF-8-encoded text, but you've given me a byte string!"

Try writing the Unicode string for the byte order mark (i.e. Unicode U+FEFF) directly, so that the file just encodes that as UTF-8:

import codecs

file = codecs.open("lol", "w", "utf-8")
file.write(u'\ufeff')
file.close()

(That seems to give the right answer - a file with bytes EF BB BF.)

EDIT: S. Lott's suggestion of using "utf-8-sig" as the encoding is a better one than explicitly writing the BOM yourself, but I'll leave this answer here as it explains what was going wrong before.

Answer 2

Read the following: http://docs.python.org/library/codecs.html#module-encodings.utf_8_sig

Do this

with codecs.open("test_output", "w", "utf-8-sig") as temp:
    temp.write("hi mom\n")
    temp.write(u"This has ♭")

The resulting file is UTF-8 with the expected BOM.

Answer 3

It is very simple just use this. Not any library needed.

with open('text.txt', 'w', encoding='utf-8') as f:
    f.write(text)

Answer 4

@S-Lott gives the right procedure, but expanding on the Unicode issues, the Python interpreter can provide more insights.

Jon Skeet is right (unusual) about the codecs module - it contains byte strings:

>>> import codecs
>>> codecs.BOM
'\xff\xfe'
>>> codecs.BOM_UTF8
'\xef\xbb\xbf'
>>> 

Picking another nit, the BOM has a standard Unicode name, and it can be entered as:

>>> bom= u"\N{ZERO WIDTH NO-BREAK SPACE}"
>>> bom
u'\ufeff'

It is also accessible via unicodedata:

>>> import unicodedata
>>> unicodedata.lookup('ZERO WIDTH NO-BREAK SPACE')
u'\ufeff'
>>> 

Answer 5

I use the file *nix command to convert a unknown charset file in a utf-8 file

# -*- encoding: utf-8 -*-

# converting a unknown formatting file in utf-8

import codecs
import commands

file_location = "jumper.sub"
file_encoding = commands.getoutput('file -b --mime-encoding %s' % file_location)

file_stream = codecs.open(file_location, 'r', file_encoding)
file_output = codecs.open(file_location+"b", 'w', 'utf-8')

for l in file_stream:
    file_output.write(l)

file_stream.close()
file_output.close()

Answer 6

python 3.4 >= using pathlib:

import pathlib
pathlib.Path("text.txt").write_text(text, encoding='utf-8') #or utf-8-sig for BOM

Answer 7

    def read_files(file_path):
    
        with open(file_path, encoding='utf8') as f:
            text = f.read()
            return text

**OR (AND)**

    def read_files(text, file_path):
    
        with open(file_path, 'rb') as f:
            f.write(text.encode('utf8', 'ignore'))

 **OR**

    document = Document()
    document.add_heading(file_path.name, 0)
        file_path.read_text(encoding='UTF-8'))
            file_content = file_path.read_text(encoding='UTF-8')
            document.add_paragraph(file_content)

**OR**

    def read_text_from_file(cale_fisier):
        text = cale_fisier.read_text(encoding='UTF-8')
        print("what I read: ", text)
        return text # return written text
    
    def save_text_into_file(cale_fisier, text):
        f = open(cale_fisier, "w", encoding = 'utf-8') # open file
        print("Ce am scris: ", text)
        f.write(text) # write the content to the file

**OR**

    def read_text_from_file(file_path):
        with open(file_path, encoding='utf8', errors='ignore') as f:
            text = f.read()
            return text # return written text

**OR**

    def write_to_file(text, file_path):
        with open(file_path, 'wb') as f:
            f.write(text.encode('utf8', 'ignore')) # write the content to the file

SOURCE HERE:

Answer 8

If you are using Pandas I/O methods like pandas.to_excel(), add an encoding parameter, e.g.

pd.to_excel("somefile.xlsx", sheet_name="export", encoding='utf-8')

This works for most international characters I believe.