Error - Save specific lines from a list | Python

Question

Basically I have this code that copies lines that contain a specific word and writes them in another file.

with open("test.txt", encoding='latin1') as f:
with open("output.txt", "a") as f1:
    for line in f:
        if str("Hello") in line:
            f1.write(str(line.encode('UTF-8')) + "\n")

So what I'm trying to do is copy lines from test.txt that contain "Hello" and paste them in output.txt. For example the output should look like this:

Hello There

He said Hello

But I have this error where each line will look like this: b'Hello There\n'

The reason I have + "\n" in the code, is because without it, the file will write them all in a single line.

Anyone know how to fix it? :(

So it outputs it like this b'Hello There\n' and im trying to get rid of the b' at start and \n' at the end The test.txt doesn't have b' or \n at the end, it just the code that does it for some reason. It's regex I believe — Kirby, Jun 20 '21 at 22:49
See the [answer](https://stackoverflow.com/a/68060635/3832970) below. — Wiktor Stribiżew, Jun 20 '21 at 22:50

score 0 · Answer 1 · answered Jun 20 '21 at 22:49

0

You do not need to convert string to bytes and back, you can use

with open("test.txt", encoding='latin1') as f:
    with open("output.txt", "a") as f1:
        for line in f:
            if "Hello" in line:
                f1.write(line)

Note you do not need to add \n here, as the newlines are kept when reading the lines with for line in f.

answered Jun 20 '21 at 22:49

Wiktor Stribiżew

607,720
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I tried this code and it does work but when I try it on some files (large files with a lot of symbols as text), some lines have a lot of symbols and when it gets there: it crashes, saves what it got and stops there (doesn't skip and continue) Here's the crash log: https://imgur.com/a/V4qsetp Is there a way to fix this? I've been trying to look it up for a while, or is there like a way to make it skip lines that it can't read or something? Thank you btw – Kirby Jun 21 '21 at 00:05
@Kirby This is a [very common issue](https://stackoverflow.com/questions/27092833/unicodeencodeerror-charmap-codec-cant-encode-characters), and I cannot help much without the exact file you have. If you can share a small version of the file, I could help more. – Wiktor Stribiżew Jun 21 '21 at 08:18

score 0 · Answer 2 · answered Jun 20 '21 at 22:49

0

When you call encode() you are effectively turning the string into a byte object. You can either specify the encoding in the with statement of the file you wish to write to, or you can call decode() after encode().

answered Jun 20 '21 at 22:49

Ralvi Isufaj

442
2
9

Error - Save specific lines from a list | Python

2 Answers2