读取然后写入 CSV 文件行 - Python3

Question

I have recently written scripts to web scrape and download different files that I need from county property appraiser websites. I now would like to add code that can read the first 2 lines and write them to a new CSV file in order for me to have some observability if any field names are added/deleted/changed. I think I'm pretty close but I've run into an error that I can't seem to figure out. Here is my code:

with open('OsceolaTaxParcels09012020.csv', 'r') as csv_file:
    csv_reader = csv.reader(csv_file)

    for i in range(2):
        rows = print(csv_reader.__next__())

    with open('Osceola_Field_Check09152020.csv', 'w') as new_file:
        csv_writer = csv.writer(new_file)

        for i in range(2):
            csv_writer.writerows(rows)

The error I keep getting is on the last line, Type Error: writerows() argument must be iterable . I figured that the 'rows' variable would be iterable because it contains the first two lines of the original csv file, but alas it is not.

Eventually, I would like to write code to compare two CSV files to each other to easily check for field changes; but that's a whole other can of worms.

Answer 1

Use writerow

Ex:

with open('OsceolaTaxParcels09012020.csv', 'r') as csv_file, open('Osceola_Field_Check09152020.csv', 'w', newline="") as new_file:
    csv_reader = csv.reader(csv_file)
    csv_writer = csv.writer(new_file)
 
    next(csv_reader) # Skip Header
    for _ in range(2):  # Iterate next 2 rows.
        csv_writer.writerow(next(csv_reader))    # Write Row

Answer 2

You do not need to use the csv module if you are trying to write the first two lines from one file to another file. You can use pathlib for high-level file operations to read from one file and write to another.

from pathlib import Path

data = """\
a,b,c
1,2,3
0,0,1
"""

# Write example data to file.
p = Path("data.csv")
p.write_text(data)

# Read contents.
file_contents = p.read_text()
all_lines = file_contents.splitlines()
first_two_lines = all_lines[:2]

# Write to a new file.
output = Path("output.csv")
output.write_text("\n".join(first_two_lines))