2

I'm currently have an issue with my python 3 code. 

 replace_line('Products.txt', line, tenminus_str)

Is the line I'm trying to turn into utf-8, however when I try to do this like I would with others, I get errors such as no attribute ones and when I try to add, for example...

.decode("utf8")

...to the end of it, I still get errors that it is using ascii. I also tried other methods that worked with other lines such as adding io. infront and adding a comma with 

encoding = 'utf8'

The function that I am using for replace_line is:

def replace_line(file_name, line_num, text):
    lines = open(file_name, 'r').readlines()
    lines[line_num] = text
    out = open(file_name, 'w')
    out.writelines(lines)
    out.close()

How would I fix this issue? Please note that I'm very new to Python and not advanced enough to do debugging well.

EDIT: Different fix to this question than 'duplicate'

EDIT 2:I have another error with the function now. 

File "FILELOCATION", line 45, in refill replace_line('Products.txt', str(line), tenminus_str) 

File "FILELOCATION", line 6, in replace_line lines[line_num] = text

TypeError: list indices must be integers, not str

What does this mean and how do I fix it?

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12
  • Show us your stracktrace, show us your data Commented Nov 15, 2016 at 23:59
  • What do you mean? Commented Nov 16, 2016 at 0:02
  • use utf_8_sig, instead of utf8, your file might start with bom Commented Nov 16, 2016 at 0:02
  • .decode('utf_8_sig') Commented Nov 16, 2016 at 0:05
  • decode('utf8', errors='ignore') Commented Nov 16, 2016 at 0:07

4 Answers 4

Reset to default
5

Change your function to:

def replace_line(file_name, line_num, text):
    with open(file_name, 'r', encoding='utf8') as f:
        lines = f.readlines()
    lines[line_num] = text
    with open(file_name, 'w', encoding='utf8') as out:
        out.writelines(lines)

encoding='utf8' will decode your UTF-8 file correctly.

with automatically closes the file when its block is exited.

Since your file started with \xef it likely has a UTF-8-encoding byte order mark (BOM) character at the beginning. The above code will maintain that on output, but if you don't want it use utf-8-sig for the input encoding. Then it will be automatically removed.

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4

codecs module is just what you need. detail here

import codecs
def replace_line(file_name, line_num, text):
    f = codecs.open(file_name, 'r', encoding='utf-8')
    lines = f.readlines()
    lines[line_num] = text
    f.close()
    w = codecs.open(file_name, 'w', encoding='utf-8')
    w.writelines(lines)
    w.close()
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5 Comments

No need for codecs in Python 3, open also supports the encoding parameter.
@MarkRansom thank you for pointing out. actually, i am a developer of python2... :)
I have another error with the function now. File "LOCATION", line 45, in refill replace_line('Products.txt', str(line), tenminus_str) File "LOCATION", line 6, in replace_line lines[line_num] = text TypeError: list indices must be integers, not str What does this mean and how do I fix it?
@NamenotFound the second parameter line_num should be an integer represent which line you need to replace. you have passed a str to the function, so it will be failed with that error. You should call the function like replace_line("Products.txt", 1, tenminus_str), it means, you want to replace the second line with string tenminus_str.
No need for codecs in Python 2, either. io.open is present in both Python 2 and Python 3 and works like Python 3's built-in open.
1

Handling coding problems You can try adding the following settings to your head

import sys
reload(sys)
sys.setdefaultencoding('utf-8')
Type = sys.getfilesystemencoding()
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1 Comment

No. Why sys.setdefaultencoding will break code
1

Try adding encoding='utf8' if you are reading a file

with open("../file_path", encoding='utf8'):
         # your code
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