在文件中查找字符串，追加到包含字符串的行的开头和结尾

Question

I have my script looking at a text file that contains a lot of text on a lot of lines. I'm trying to get it so whenever the word "ERROR" is found, it appends to the beginning and end of the line containing "ERROR"

So far I have a variable that returns a list of all lines that contain "ERROR"

with open(infile, 'r') as f:
    targets = [line for line in f if "ERROR" in line]

so if I print targets it will return a list of all of the lines that contain "ERROR".

targets[0] returns the first line etc.

I've also been able to apply the formatting:

for i in targets:
    format = '<span style="background-color: #ff0000; color: #ffffff;">' + i + '</span>'
    formatted_line = i.replace(i, format)

But I can't seem to figure out how to have the script write a new file with all of the text including the formatting that was added to the start and end.

Just need a point in the right direction! Thanks

EDIT: some clarification on the desired output:

original file:

log line of text here

log line of text here

error line of text here

log line of text here

error line of text here

log line of text here

new file:

log line of text here

log line of text here

<span style="background-color: #ff0000; color: #ffffff;">error line of text here</span>

log line of text here

<span style="background-color: #ff0000; color: #ffffff;">error line of text here</span>

log line of text here

Answer 1

with open(infile, 'r') as IN, open('output.txt', 'w') as OUT:
    for line in IN:
        if "ERROR" in line:
            f = '<span style="background-color: #ff0000; color: #ffffff;">' + line + '</span>'
            OUT.write(f + '\n')
        else:
            OUT.write(line + '\n')

Answer 2

Just add a .split() function to the line in the if statement to convert it into an array rather than a string.

with open(infile, 'r') as f:
    targets = [line for line in f if "ERROR" in line.split()]

print(targets)

Answer 3

I think splitting the logic of reading and writing is more readable. And...readability is very important in coding.

I saved your text in a text file called text.txt and I saved the output in new_text.txt . I didn't know exactly what format you wanted for the result (mostly spacing), so you can play around with that to see what fits your needs.

from pathlib import Path

# Get stored text
text_fp = Path.home().joinpath('Desktop','text.txt')

lines = []
with open(text_fp,'r') as fp:
    for line in fp:
        if 'error' in line:
            line = '<span style="background-color: #ff0000; color: #ffffff;">{}</span>'.format(line)
        lines.append(line)

# New file name
new_text_fp = Path.home().joinpath('Desktop','new_text.txt')
with open(new_text_fp,'w') as fp:
    for line in lines:
        fp.write('{}\n'.format(line))

Input data:

log line of text here
log line of text here
error line of text here
log line of text here
error line of text here
log line of text here

Result:

log line of text here

log line of text here

<span style="background-color: #ff0000; color: #ffffff;">error line of text here
</span>
log line of text here

<span style="background-color: #ff0000; color: #ffffff;">error line of text here
</span>
log line of text here