Writing a string to a file goes to the wrong spot

July 11, 2022

I have a python script that takes a csv file and adds a string to it. The only issue is the string that I add is at the end of the string. I would like it to be in the front of the string instead of the end.

Here is the script:

#Adding string to the front of each line for the Part Numbers
string_to_add = r"V:\DATABASES\0 Suspension\Suspensia Pictures\ "

#Open the file and join the .JPG to the current lines
with open("PartNumbers.csv", 'r') as f:
    file_lines = [''.join([x.strip(), string_to_add,'\n']) for x in f.readlines()]

with open("PartNumbers.csv", 'w') as f:
    f.writelines(file_lines)

It gives me this output:

X00TB0001V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0003V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0004V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0005V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0006V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0007V:\DATABASES\0 Suspension\Suspensia Pictures\ 
X01BJ0008V:\DATABASES\0 Suspension\Suspensia Pictures\

This is the output I am looking for:

V:\DATABASES\0 Suspension\Suspensia Pictures\ X00TB0001
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0003
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0004
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0005
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0006
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0007
V:\DATABASES\0 Suspension\Suspensia Pictures\ X01BJ0008

My original idea was to change around the line

file_lines = [''.join([x.strip(), string_to_add,'\n']) for x in f.readlines()]

to this:

file_lines = [ string_to_add,''.join([x.strip(),'\n']) for x in f.readlines()]

When I do that I get this error:

file_lines = [string_to_add,''.join([x.strip(), '\n']) for x in f.readlines()]
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SyntaxError: did you forget parentheses around the comprehension target?

How can I edit this script to get the desired output?