以'200'开头时将行追加到上一行

Question

My Problem is the following:
I have a csv-file with lines that normally start with '200'. In this file there are unwanted linebreaks.

Eg

200 Peter Pan 
200 John Smith 
200 Susan Murray 
200 Harald  
Williams
200 Liam Noah

That's how the file should look at the end:

200 Peter Pan
200 John Smith
200 Susan Murray
200 Harald Williams
200 Liam Noah

So whenever a line does not start with '200' it should be appended to the previous line. I hope this should be quite easy with Python but I'm not getting it right so far.

Answer 1

with open(<file_name>, 'r+') as file:
    text = str();
    for line in file:
        if line[0:3] == "200":
            text = "{}\n{}".format(text, line.strip());
        else:
            text = "{} {}".format(text, line.strip());
    file.seek(0);
    file.write(text[1:]);

Answer 2

The following code will do the job...

With a file called file.csv , with contents:

200 Peter Pan 
200 John Smith 
200 Susan Murray 
200 Harald  
Williams
200 Liam Noah

after we run the following script :

lines = open("file.csv", "r").read().split("\n")
for i, line in enumerate(lines):
   if not line.startswith("200"):
      lines[i-1] = lines[-1].strip() + " " + line
      lines.pop(i)

open("file.csv", "w").write("\n".join(lines)+"\n")

the file is updated as you wanted it to be to:

200 Peter Pan
200 John Smith
200 Susan Murray
200 Harald Williams
200 Liam Noah

How does it work?

The steps:

• read in the .csv file as a string and convert it to a list of lines by splitting the string on the new-line ( '\\n' ) character.
• iterate through the enumerated lines list so we have two variables to work with: the index and the lines.
• check if the line starts with "200" .
• if it does, append the line to the line one index before (by stripping the line before and adding a space between), and then remove the line from the list of lines by popping its index .
• finally, we open the same .csv file for writing and write to it the new lines . The string from the list of the lines is got by adding a new-line character between each line and finally adding an extra one at the end.

Hope this helps you out!

Answer 3

Read csv file and iterate over lines:

with open('test.csv', 'r') as f:
    f_csv = csv.reader(f)
    # header = next(f_csv)
    for row in f_csv:
        if not row.startswith(200):
            #append previous row

Answer 4

The code that works perfectly fine for me is the following:

with open('testing2.CSV', 'r+', encoding="utf-8") as file:
    text = str();
    for line in file:
        if line[0:3] == "200":
            text = text + '\n';
        text = text + line.strip();
    file.seek(0);
    file.write(text);

It even keeps the first line which is nice as my CSV file has headers. Thanks to everyone who helped here especially Benjamin James Drury and Joe Iddon.