Python-Web抓取表格并将仅特定的列写入CSV文件

Question

I'm having a few issues. First off, when I try to write a CSV file from a web scraping, nothing is written. The file does save, but it's completely blank. Ultimately, I'm hoping to open it and call on the water temperature column to calculate an average.

My other issue is that I only want a few of the columns from the table in my CSV file. Can someone verify that what I did is correct? I only want the first 3 columns, and then the 14th column.

Thank you!

import sys
import urllib2
import csv
import requests 
from bs4 import BeautifulSoup

r_temp1 = requests.get('http://www.ndbc.noaa.gov/data/realtime2/BZBM3.txt')
html_temp1 = r_temp1.text
soup = BeautifulSoup(html_temp1, "html.parser")
table_temp1 = soup.find('table')
rows_temp1 = table.findAll('tr')
rows_temp1 = rows_temp1[1:]

#writing to a csv file
csvfile_temp1 = open("temp1.csv","wb")
output_temp1 = csv.writer(csvfile_temp1, delimiter=',',quotechar='"',quoting=csv.QUOTE_MINIMAL)
for row in rows_temp1:
    Year = cells[0].text.strip()
    Month = cells[1].text.strip()
    Day = cells[2].text.strip()
    W_temp = cells[14].text.strip()
    output.writerow([Year,Month,Day,W_temp])
csvfile_temp1.close()

Answer 1

Running your code gives:

File "hh.py", line 11, in <module>
rows_temp1 = table.findAll('tr')

NameError: name 'table' is not defined

And indeed in line 10 you define table_temp1, and not table. Don't know if you have other issue, but start by reading the errors you get

Answer 2

You're not seeing anything in the file because there are no rows in rows_temp1 . That array is empty because there are no table rows in a text file. It looks like you are expecting an HTML file with a table, but the file is just a plain text file.

Here is a version that does what you want:

import csv
import requests

r_temp1 = requests.get('http://www.ndbc.noaa.gov/data/realtime2/BZBM3.txt')
rows_temp1 = r_temp1.text.split('\n')

#writing to a csv file
csvfile_temp1 = open("temp1.csv","wb")
output_temp1 = csv.writer(csvfile_temp1, delimiter=',',quotechar='"',quoting=csv.QUOTE_MINIMAL)
for row in rows_temp1:
    if not row:  continue
    cells = row.split()
    Year = cells[0].strip()
    Month = cells[1].strip()
    Day = cells[2].strip()
    W_temp = cells[14].strip()
    output_temp1.writerow([Year,Month,Day,W_temp])
csvfile_temp1.close()